New in PMC

March 21, 2024

Preview Upcoming Improvements to PMC

We are pleased to announce the availability of a preview of improvements planned for the PMC website. These improvements will become the default in October 2024 and include an updated article display and enhanced PMC journal list. Click on the "Try it out now" link in the banner on the top of any page on the current PMC website to preview these updates, and visit NCBI Insights for more information.

December 15, 2023

Update on PubReader Format

The PubReader format was added to PMC in 2012 to make it easier to read full text articles on tablet, mobile, and other small screen devices.

In March 2022, NCBI launched an updated PMC website. The updated website is mobile responsive, making it easy to read articles in PMC on any device. This makes some legacy features, such as the PubReader view, no longer necessary.

In January 2024, we will remove the PubReader links from the PMC website. You will temporarily still be able to access the PubReader format by appending "?report=reader" to any PMC article URL (e.g., https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9825438/?report=reader).

In May 2024, we will fully remove the PubReader functionality from the PMC website. Any link to the PubReader format will redirect to the standard, mobile responsive, PMC article view.

August 30, 2023

Update on Access to Coronavirus-related Articles in PubMed Central (PMC) COVID-19 Collection after end of Public Health Emergency

Early in the COVID-19 pandemic, the National Library of Medicine (NLM) collaborated with publishers and scholarly societies to expand access to coronavirus-related journal articles in PubMed Central (PMC). Through this collaboration, more than 50 publishers made more than 350,000 coronavirus-related articles accessible under various license terms through the PMC COVID-19 Collection (previously the PMC COVID-19 Public Health Emergency Initiative).

As COVID-19 emergency declarations expired in the United States and around the globe, so too did article-level license terms for use of some of these articles. Most of the articles deposited in the PMC COVID-19 Collection will remain available in PMC, and all citations will remain searchable in PubMed and available for bulk distribution and reuse through the PMC Open Access Subset. However, some publishers retained the right to remove their content and have requested to do so.

Details on changes to the licensing status or availability of content can be found in the NLM Technical Bulletin. More information, including a list of publishers and their licensing statuses, is available in the PMC COVID-19 Collection FAQs and on the PMC COVID-19 Collection webpage.

May 03, 2023

PMC Public Health Emergency Initiatives Update

The National Library of Medicine (NLM) recently renamed the COVID-19 and Mpox Public Health Emergency Initiatives as the PMC COVID-19 Collection and PMC Mpox Collection, respectively. NLM continues to work with publisher and scholarly society collaborators who contribute content to these collections to provide broad access and support reuse of relevant scientific literature.

April 19, 2023

Clarifying PMC's Role as an Archive

The role of what a library means in a digital world is evolving and expanding. PMC has a large and diverse user base that includes students and the public, as well as researchers, clinicians, and librarians. We recognize that these different audiences have varying levels of familiarity with NLM, the National Institutes of Health (NIH), and the scholarly publishing process and have recently updated how we describe, display, and share articles in PMC to provide our users with more context. Visit NCBI Insights for more information about these updates.

January 30, 2023

Second Phase of the NIH Preprint Pilot Launched

Today, we are pleased to announce the launch of the second phase of the NIH Preprint Pilot with the addition of more than 700 new preprint records to PubMed Central (PMC) and PubMed. This second phase expands the scope of the Pilot to include preprints resulting from all NIH-funded research. Eligible preprints are those acknowledging direct support of an NIH award or authored by NIH staff and posted to bioRxiv, medRxiv, arXiv, or Research Square, on or after January 1, 2023. NLM will automatically include the full text of the preprint (as license terms allow) and associated citation information in PMC and PubMed, respectively. New preprint records will be added on a weekly basis. Phase 2 of the pilot is expected to run through 2023. A project of NLM, the NIH Preprint Pilot was launched in 2020 to explore new approaches to increase the discoverability of NIH-supported research results, with the first phase focusing on NIH-supported research on COVID-19 and the SARS-CoV-2 virus.

To learn more, visit the NIH Preprint Pilot page.

January 10, 2023

Next Phase of NIH Preprint Pilot Launching Soon

Last month, the National Library of Medicine (NLM) announced plans to extend its NIH Preprint Pilot in PubMed Central (PMC) and PubMed beyond COVID-19 to encompass all preprints reporting on NIH-funded research. The second phase of the pilot, launching later this month, will include preprints supported by an NIH award, contract, or intramural program and posted to an eligible preprint server on or after January 1, 2023.

In preparation for the launch of this second phase, we have updated PMC and PubMed site features to help users of these databases incorporate the increased volume of preprints into their discovery workflows. See the NCBI Insights post for more information about these preprint record display and search filter updates.

PMC will continue to update the NIH Preprint Pilot Overview and FAQs in the coming weeks. Please send your questions and feedback to pmc-preprints@ncbi.nlm.nih.gov.

September 08, 2022

PMC Collaborating with Publishers in Response to Mpox Public Health Emergency

On August 4, 2022, the White House Office of Science and Technology Policy (OSTP) announced a coordinated call to action with the science and technology leaders of more than 20 countries, requesting that publishers voluntarily make mpox and other orthopox-related publications freely and immediately accessible in appropriate public repositories to support the ongoing public health emergency response efforts. The call specified that these articles be made available with broad reuse rights in both human- and machine-readable formats to allow access to full text content and metadata.

Publishers have responded to the call by volunteering to make their relevant articles accessible in PMC in formats and under license terms that facilitate text mining and secondary analysis. PMC-participating publishers can email PMC at pmc-phe@ncbi.nlm.nih.gov to notify us of their interest in collaborating on this effort.

For a list of current collaborators, help with querying mpox-related literature, and more information, please visit our Public Health Emergency Mpox Initiative webpage.

August 30, 2022

PMC Releases Improved Related Resources Feature

PMC has released an updated feature to make it easier to explore information related to a given article. You will now see three sections in the right-hand column of all PMC articles which can be opened to browse similar articles in PubMed, articles that cite the current article, and links to related data records in National Center for Biotechnology Information (NCBI) databases.

See our post in the NLM Technical Bulletin for more details about the update, and please continue to provide feedback through the Feedback button found on the PMC website.

March 22, 2022

New PMC Website Design is Live!

We have launched a fresh look and feel to the PubMed Central (PMC) website, which marks the first step of an ongoing modernization effort. Now when you visit PMC's website, you will see:

a redesigned and reorganized homepage
easy-to-navigate help documentation
a similar look and feel between features in PMC and PubMed
a streamlined article display

See our post in NCBI Insights for more details about the update, and please continue to provide feedback through the green "Feedback" button in the lower right-hand corner of the PMC website.

February 24, 2022

Public Access in PMC Update

In 2021, PubMed Central (PMC) continued to grow and evolve in its role as a repository for research support by the National Institutes of Health (NIH) and other partner funding agencies. Around 1.3 million articles have been made publicly accessible in PMC under the NIH Public Access Policy; and the volume of NIH-supported articles added to PMC with associated data content continues to increase annually (59% of articles in 2020 included supplementary material and/or a data availability statement vs. 27% in 2009). Other recent activities include:

Release of a new training video that walks users through the NIH Manuscript Submission (NIHMS) system deposit workflow, as well as updated tutorials.
Modifications to the NIHMS system to support new funder requirements (e.g., see the updated Howard Hughes Medical Institute Open Access Policy that took effect January 1, 2022; a supplemental tutorial is also now available for HHMI submitters).
Expansion of the Health Research Alliance (HRA) Open program to support the open access policies of The Association for Frontotemporal Degeneration and IRIDIAN GENOMES.
New submissions to NASA PubSpace have moved from the NIHMS system to the NASA Science and Technology Information Program. Further information is available on the NASA STI Program website.
Release of the PMC Funder Deposit List to help publishers, funders, and institutions identify the funded content that can be deposited in PMC and clarify the available submission routes.

Over the last year, PMC has also continued to pilot the curation and ingest of NIH-support preprints reporting COVID-19 research. There are now over 3,000 preprint records discoverable in PMC, accelerating and expanding discovery of NIH research.

September 21, 2021

New Directories and File Packages for Bulk Retrieval of the PMC Article Datasets

[Story Updated April 1, 2022]

PubMed Central (PMC) has made significant improvements to the bulk retrieval of two of the PMC Article Datasets from our FTP service. The improvements were made to bulk packages which include metadata and full text of articles in XML or plain text formats for the PMC Open Access (OA) Subset and the Author Manuscript Dataset, which combined encompass more than half of the 7 million articles in PMC. To improve the usability of these two datasets, PMC has redesigned the bulk download directory structure and file packages on our FTP service. The new structure includes:

baseline packages that contain all articles available in PMC as of the baseline date for each respective dataset or grouping; and
daily incremental packages for each respective dataset or grouping that only contain articles that are new to the dataset or that have been updated since the baseline or previous incremental file was created.

The PMC Open Access Subset bulk packages have been divided into three groups based on available license terms:

Commercial Use Allowed - CC0, CC BY, CC BY-SA, CC BY-ND licenses;
Non-Commercial Use Only - CC BY-NC, CC BY-NC-SA, CC BY-NC-ND licenses; and
Other - no machine-readable Creative Commons license, no license, or a custom license.

The baseline packages for each of these PMC Open Access Subset usage groups and for the Author Manuscript Dataset have been further divided by PMCID range (e.g., a package with PMC004XXXXXX in its name means that any appropriate articles with PMCIDs falling between PMC4000000 and PMC4999999 are included in the package).

The previous bulk download directories and packages were moved to a new temporary location in December 2021 and were deleted on April 1, 2022. This change does NOT impact the individual PMC Open Access Subset article directories and packages on the PMC FTP service, those will remain unchanged. Please also note that the datasets discussed in this update are also now available for retrieval and computing in the cloud.

See the PMC FTP Service page for more details. Please send your feedback and share more about how you are using the PMC Article Datasets to pubmedcentral@ncbi.nlm.nih.gov.

June 14, 2021

PMC Labs is here - Let Us Know What You Think!

[Update March 14, 2022: On March 21, 2022, we will be releasing an updated PMC website design, which has been in development on PMC Labs since June. Please see NCBI Insights to learn more.]

NCBI is at work on a PMC update aimed at creating a more modern and accessible user experience. The first phase of this work is now available on PMC Labs, https://www.ncbi.nlm.nih.gov/labs/pmc, for you to explore and provide feedback. See our post on NCBI Insights for details about key features in PMC Labs and more about our plan for updating the site.

Trying Out PMC on Labs

We encourage you to explore the site and provide feedback. Buttons on the lower right-hand side of the screen make it easy to provide feedback or navigate back to the current PMC site.

To return to the PMC website after visiting PMC on Labs, click the red "Exit PMC Labs" button or the link in the banner at the top of the page.

June 15, 2020

NIH Preprint Pilot Launched

On June 9, 2020, NLM launched the NIH Preprint Pilot. During the pilot, NLM will make preprints resulting from research funded by the National Institutes of Health (NIH) available via PubMed Central (PMC) and, by extension, PubMed. The pilot aims to explore approaches to increasing the discoverability of early NIH research results. The pilot will run for a minimum of 12 months. Lessons learned during that time will inform future NLM efforts with preprints.

To learn more about the pilot, see:

To find preprints in PMC, you can search: preprint[filter]. You can exclude preprints from search results by using the Boolean NOT, e.g., covid-19 NOT preprint[filter]. For additional information on filtering preprints in PMC and PubMed see the FAQ.

Regular updates on the pilot status will be posted to the NLM Technical Bulletin. We encourage you to send your feedback to pmc-preprints@ncbi.nlm.nih.gov.

March 26, 2020

PMC Collaborating with Publishers in Response to COVID-19 Public Health Emergency

On March 13, 2020, the National Science and Technology Advisors from a dozen countries, including the United States, called on publishers to voluntarily agree to make their COVID-19 and coronavirus-related publications and associated data immediately accessible in PubMed Central (PMC) and other appropriate public repositories to support the ongoing public health emergency response efforts.

For more information on which publishers have responded to this call and how to discover COVID-19 and coronavirus-related publications in PMC, see the main COVID-19 Initiative page.

A FAQ is also available. If you have questions not addressed in the FAQ, please contact pmc-phe@ncbi.nlm.nih.gov.

You can learn more about how this initiative fits into the wider NLM response to the current public health emergency in Dr. Patti Brennan's post, "How Does a Library Respond to a Global Crisis?"

July 31, 2019

PMC Tagging Guidance for Peer Review Documents Now Available

Peer review documents, including review reports and editor decision letters, are increasingly being published along with the articles they review. This practice is intended to make the publishing process more transparent. To support these efforts, PMC's Tagging Guidelines have been updated to include the tagging of peer review documents. NLM encourages PMC-participating publishers, journals, and data providers to review this guidance. Please contact us at pubmedcentral@ncbi.nlm.nih.gov if you have any questions.

February 04, 2019

Unique Identifiers for Supplemental Material

PMC has updated the Associated Data box to display unique identifiers assigned to supplemental material files by the publisher when available (e.g., DOI; see PMC6351104). In cases where the publisher has not assigned a unique ID to a supplemental file, NLM will generate and display a Globally Unique Identifier (GUID; see PMC6351564). This update aims to support the reporting of datasets as well as the citation and discovery of this content.

Publishers that are interested in supplying unique IDs for supplemental material files with their PMC submissions should visit the Tagging Guidelines.

January 14, 2019

Open Access Subset FTP Clean Up

On March 18, 2019, PMC will no longer provide bulk packages of Open Access (OA) Subset text and XML at the top level directory of the FTP Service. These files were superseded in August 2016 by the Commercial Use and Non-Commercial Use bulk packages located in the oa_bulk subdirectory. One set comprises articles that may be used for commercial purposes (the Commercial Use Collection); the other contains articles that can be used only for non-commercial purposes. Anyone planning to use OA subset content for non-commercial purposes will need to download both "non_comm_use.*.tar.gz" and "comm_use.*.tar.gz" to access the complete collection. See the Open Access Subset page for additional details. Questions should be directed to pubmedcentral@ncbi.nlm.nih.gov.

January 07, 2019

PMC Adds Support for Machine-Readable Clinical Trial Information

Machine-readability of scholarly outputs is critical to supporting large-scale analysis of the scientific literature. To that end, PMC's Tagging Guidelines and internal processes have been updated to support the JATS4R recommendations for tagging clinical trial information. NLM encourages PMC-participating publishers, journals, and data providers to review this guidance. Please contact us at pubmedcentral@ncbi.nlm.nih.gov if you have any questions.

November 15, 2018

Discovering Associated Data in PMC

In the NLM Strategic Plan released earlier this year, we noted that "[c]reating efficient ways to link the literature with associated datasets enables knowledge generation and discovery." To that end, PMC is now aggregating data citations, data availability statements and supplementary materials, as available, in an Associated Data box. This box will only display on articles that have one or more of these features in the article.

To limit your search to records with an Associated Data box, you can use the new "Associated Data" facet on the search results page:

We hope that exposing this content in a consistent format and in an easy to find and easy to access manner, you will more readily find the datasets you need to further accelerate discovery and advance health. As part of our ongoing commitment to making data findable, accessible, interoperable, and re-usable (FAIR), we encourage you to contact us with your feedback on these updates and with any other suggestions you may have for improving discovery of related data in PMC.

October 23, 2018

Open Access Week 2018 and PMC

Collaboration with publishers and funders to ensure the openness and preservation of the scientific record is one of PMC's core principles. Open Access Week offers an opportunity to celebrate some of the recent outcomes of these collaborations:

In July 2018, the PMC corpus of publicly accessible articles hit 5 million articles.
In May 2018, the PMC Open Access Subset surpassed the 2 million article mark.
The Author Manuscript Collection now includes more than 500,000 papers for text mining.
The PMC and Research Funder Policy page underwent an update in September 2018 to increase transparency around funder support in PMC for publishers, authors, and the public.
Funder policy support in PMC has been extended to the US Department of Homeland Security, in addition to several new US private research funders via the Health Research Alliance.

In FY2018 more than 200 new journals committed to archiving their complete contents in PMC, to be made publicly accessible in 12 months or less.

June 26, 2018

Updated information on journal selection and participation agreements released

PMC has released expanded information about its selection process for journals that apply for participation. The current review process has been in place since November 2014 and focuses on the scientific rigor and editorial quality of each journal that applies to participate in PMC. Some of the attributes taken into account as part of this process include the article content, journal policies, language quality, and presentation of content. The same assessment considerations are used for reevaluation of currently participating journals. We encourage you to visit the Journal Selection for PMC page to learn more.

Publishers and journals interested in submitting an application to PMC are also encouraged to review our updated policies on agreement types. These policies provide the eligibility criteria for each type of participation agreement and should be considered alongside the pre-application requirements.

We hope these updates are informative and look forward to hearing your feedback.

April 18, 2018

Data Filters in PMC and PubMed

Looking for journal articles with associated data sets? New search filters in PMC and PubMed aim to increase the discoverability of articles with associated data information.

In PMC, users can now search on or append searches with filters to discover articles with specific types of associated data, i.e., to find

articles with associated supplementary material, use "has suppdata"[filter];
articles that include a data availability or data accessibility statement, use "has data avail"[filter]; or
articles that include data citation(s), use "has data citations"[filter]

Alternatively, users can run a search on "has associated data"[filter] to find all articles with any type of data section described above.

In PubMed, users can now search on or append searches with data[filter] to find articles with related data links in either the Secondary Source ID field or the LinkOut -- Other Literature Resources field (both located below the abstract). These data links may be to records in other NLM databases (e.g., GenBank) or external data repositories (e.g., figshare, Dryad).

The provision and availability of associated datasets still varies widely from article to article, but it is our hope that this small step helps improve the discoverability of this material and supports wider community efforts to advance science in new directions.

March 28, 2018

Article Display Updates

In collaboration with Europe PMC, PMC has rolled out several updates to our article display in order to enhance the transparency and readability of the content.

Navigating from the PMC record to the PubMed record has been made easier by the addition of hyperlinked PubMed IDs (PMIDs) in the upper right-hand corner of article records. Clicking the PMID link will take you to the corresponding citation record in PubMed.

The PMC Disclaimer link has also been moved out of the Copyright and License information section for easier discovery and access. This page describes what content is included in PMC as well as other important NCBI and NLM disclaimer information.

Additionally, two changes have been implemented to improve the functionality of author names. Users can now click on an author name to view the author's affiliation(s). Users also have the option of running a quick author name search in PMC by clicking the linked author name in "Find articles by [author name]". In the example pictured above, the search would be for "Sawyer SL"[Author].

And finally, figures and tables have been moved inline in the article display. By moving away from the thumbnail display, PMC hopes to make it easier for users to view figure and table data as they read articles. Users may still click on the figure/table title or "Open in separate window" (as available) link for a closer look.

We hope these updates improve the overall user experience in PMC and look forward to hearing your feedback.

References

Screenshots from:

Qiao, Y., Yang, J., Liu, L., Zeng, Y., Ma, J., Jia, J., … Wang, Y. (2018). Successful treatment with pazopanib plus PD-1 inhibitor and RAK cells for advanced primary hepatic angiosarcoma: a case report. BMC Cancer, 18, 212. http://doi.org/10.1186/s12885-018-3996-3

Stabell, A. C., Meyerson, N. R., Gullberg, R. C., Gilchrist, A. R., Webb, K. J., Old, W. M., … Sawyer, S. L. (2018). Dengue viruses cleave STING in humans but not in nonhuman primates, their presumed natural reservoir. eLife, 7, e31919. http://doi.org/10.7554/eLife.31919

Both articles made available under a CC-BY license.

January 04, 2018

PMC Year in Review

As we kick off a new year, we wanted to take this opportunity to look back on 2017, which was a milestone year for PMC.

Last year, PMC made nearly half a million articles available for the public to access with the support of participating journals, publisher programs, and research funders. Also, in addition to expanding support for public access to research results and the linking of those results to the underlying dataset(s), PMC released several other policy and resource updates. These include:

Clearer statement of scope for PMC (see also the updated entry in the NLM Collection Development Manual for "Journals");
Guidance for journals on reapplying to PMC;
Policy statements on the scientific, editorial, and technical standards for PMC (including details on the journal reevaluation process), the supply of back content, the eligibility of non-English language journals, and the maintenance of publishing schedules;
Production data requirements for PMC-participating journals; and
Major update to the PMC Article Previewer, a tool that allows publishers to see or "preview" how articles will appear in PMC and resolve data problems prior to submission.

In September, NLM recognized the achievements to date in the Wellcome Trust and NLM Biomedical Journal Digitization project, which has added a dozen new historical titles and more than a half million pages to the PMC archive. The PMC archive now includes content from as far back as the late 18th century.

Many thanks all our participants and users for a wonderful year!

December 18, 2017

PMC Canada Status Update

PMC Canada, sponsored by the Canadian Institutes of Health Research (CIHR), with operational support provided by the National Research Council (NRC), has been a valued partner in the PMC International network since 2009. CIHR and NRC have now notified NLM of their decision to permanently take PubMed Central Canada (PMC Canada) offline on February 23, 2018. Details of this decision are available on the PMC Canada website.

The decision to decommission PMC Canada does not affect the status or operations of NIH's PubMed Central (US) or Europe PubMed Central. PMC Canada content will remain in the PMC archive and be publicly searchable on NLM's PubMed Central (US) and through Europe PMC. CIHR researchers who publish in journals that deposit their articles directly into NIH's PubMed Central or deposit manuscripts co-funded with current PMC-participating funders will continue to be considered in compliance with the Tri-Agency Open Access Policy on Publications.

NIH and NLM have appreciated our cooperation with CIHR and NRC over the last several years and will continue to identify new opportunities to work together to support open access and research excellence.

October 30, 2017

Updated guidance on data deposit and linking in PMC

In response to the growing interest in the availability of data associated with articles, PMC is reviewing current practices around data and seeking feedback on how to best serve the data needs of the research community.

As part of these efforts, the PMC policy statement on supplementary data was recently updated to more clearly articulate the requirement that any supplementary data (images, tables, video, or other documents / files) that are associated with an article must be deposited in PMC with an article. The search filter "has suppdata[filter]" can be used in PMC to discover records with associated supplementary data files.

In addition to providing supplementary data with an article, NLM is also encouraging journals and authors to make research data available in a public repository and include the relevant data citation(s) in the paper. Guidance for PMC data providers on tagging data citations is available in the Tagging Guidelines. This guidance is based on the JATS4R recommendations on data citations.

Starting this month, the NIH Manuscript Submission (NIHMS) system will also accept deposits of small datasets accompanying deposits of funded author manuscripts for inclusion of PMC. (Guidance for authors is available in the NIHMS FAQ.)

If you have suggestions on future directions in data for PMC to consider, please let us know at pubmedcentral@ncbi.nlm.nih.gov.

August 28, 2017

PMC Continues to Expand its Role as a Repository for Federally and Privately-funded Research

Since March 2016, the NIH Manuscript Submission (NIHMS) system has added support for researchers from the following federal agencies to deposit in PMC any manuscripts that fall under the agency's public access policy:

Assistant Secretary for Preparedness and Response (ASPR/HHS; intramural only at this time)
Environmental Protection Agency (EPA; intramural only at this time)
National Aeronautics and Space Administration (NASA; intramural/civil servants and grantees)

Manuscript deposit support for all Administration for Community Living (ACL/HHS) researchers will be available in NIHMS by October 2017 and for Department of Homeland Security researchers in early 2018.

Additionally, the Bill & Melinda Gates Foundation Open Access Policy now requires their grantees to make their published research results available in PMC immediately upon publication under a Creative Commons Attribution (CC-BY) license. Manuscript deposit support is not provided in NIHMS for Gates-funded researchers; rather the final published version of any Gates-funded article is to be deposited directly to PMC by the publisher or a funder-supported data provider without author involvement. More information on this open access policy is available on the Gates Foundation website.

PMC will continue to update the list of participating funding agencies at Public Access and PMC as support is implemented.

January 19, 2017

PMC Bulk Download via FTP is Now Using New Naming Conventions

A large-scale update of the file names used for articles available via the PMC FTP service for bulk download was undertaken in early January 2017. The new file naming convention is PMCID-based (e.g., PMC4855680.tar.gz) rather than being built from article citation data (i.e., journal abbreviation_pub date_volume_issue_page). This update was made following user reports that the previous naming convention was resulting in missing contents in cases where citation data was duplicated across multiple articles. The new convention will ensure that file names are unique and that the corpus available via the FTP service is complete.

August 17, 2016

New Search Result Filters and Updated Reference List Display

As of August 2016, PMC is home to four million articles! To make this wealth of full-text content easier to navigate, PMC has rolled out a few updates:

1) Search Result Filters
On all search results pages, you will now see filters (similar to PubMed's filters) on the left-hand side that allow you to filter your results by article attributes, publication date, research funder, and search fields. These filters replace the Limits page and allow you to more readily:

find open access articles (PMC has more than 1.35 million open access articles that can be reused according to their license statements),
explore PMC's rich historical content from NLM's back issue digitization project,
browse research supported by PMC-participating funding organizations (click "Customize" to view additional funder options),
and much more.

You can now also quickly add articles that are under a 12-month or less embargo in PMC to your search results by selecting the "Include embargoed articles" filter option under Text Availability. See the PMC User Guide for more information on these filters.

2) Reference List Display
Using related article data available in PMC, articles that cite papers that have been either retracted or named in a Findings of Research Misconduct issued by the HHS Office of Research Integrity and not yet retracted will now include a red hyperlink to the relevant notice directly from the article's reference list. This update will help users more easily identify post-publication updates to existing research.

August 01, 2016

FTP service update to improve access to text mining collections

PMC has reorganized its FTP Service site for users interested in accessing the PMC Article Datasets, which include the original Open Access (OA) Subset. New top-level FTP directories help users quickly locate the content available for bulk download that best suits their research needs. These directories include:

oa_package - article packages for individual OA articles
oa_pdf - individual PDFs for OA articles
oa_bulk - bulk packages of text from OA articles
manuscript - author manuscripts collected under a funding agency's public access policy
historical_ocr - select OCR texts from the PMC Back Issue Digitization project

To make it easier for users to identify and comply with the different licenses that apply to OA articles, new file lists have been created and the file lists for individual OA articles now include a "license-type" field for each article. Similarly, the bulk packages of OA article text have been divided into two sets. One set comprises articles that may be used for commercial purposes (the Commercial Use Collection); the other contains articles that can be used only for non-commercial purposes. See the Open Access Subset page for details.

To allow regular users to transition to the new arrangement, the previous arrangement of files and directories will be maintained in parallel for at least four weeks (i.e., until the end of August 2016).

March 24, 2016

Public Access Expansion and PMC

Last month marked the third anniversary of the White House's Office of Science and Technology Policy (OSTP) memorandum directing Federal agencies with more than $100 million in annual research and development (R&D) expenditures to develop plans for increasing public access to the results of the research they support, including scholarly publications. As a result of this directive, in 2015, PMC started providing support as a public access repository for funding agencies beyond the National Institutes of Health (NIH) and Howard Hughes Medical Institute (HHMI).

As of March 2015, the following additional agencies are using the NIH Manuscript Submission (NIHMS) system to facilitate the deposit in PMC of peer-reviewed manuscripts that fall under their public access policies:

Agency for Healthcare Research Quality (AHRQ/HHS)
Centers for Disease Control and Prevention (CDC/HHS),
Food and Drug Administration (FDA/HHS),
National Institute of Standards and Technology (NIST), and
U.S. Department of Veterans Affairs (VA)

Additionally, the following additional HHS and other federal agencies have announced public access plans and committed to using PMC as the repository for agency-funded publications:

Administration for Community Living (ACL/HHS)
Assistant Secretary for Preparedness and Response (ASPR/HHS)
Environmental Protection Agency (EPA)
National Aeronautics and Space Administration (NASA)

PMC will continue to update the list of participating funding agencies at Public Access and PMC as these agencies begin implementation of their policies.

More information about the current status of public access expansion as a result of the OSTP memo can be found on the White House blog.

January 11, 2016

NIH Author Manuscripts Available for Text Mining

NIH-supported scientists have made over 300,000 author manuscripts available in PMC. Now NIH is making these papers accessible to the public in a format that will allow robust text analyses.

You can download the PMC collection of NIH-supported author manuscripts as a package in either XML or plain-text format at ftp://ftp.ncbi.nlm.nih.gov/pub/pmc/manuscript/. The collection encompasses all NIH manuscripts posted to PMC that were published in July 2008 or later. While the public can access the manuscripts' full text and accompanying figures, tables, and multimedia via the PMC website, the newly available XML and plain-text files include full text only. In addition to text mining, the files may be used consistent with the principles of fair use under copyright law.

Please note that these author manuscript files are not part of the PMC Open Access Subset.

The NIH Office of Extramural Research developed this resource to increase the impact of NIH funding. Through this collection, scientists will be able to analyze these manuscripts, further apply NIH research findings, and generate new discoveries.

For more information, please visit the PMC author manuscript collection webpage.

December 15, 2015

Updated PMC journal review process and minimum requirements

The PMC Overview and FAQ have been updated to provide more information on the Scientific Quality Review Process for journals that apply to participate in PMC.

In 2014, PMC implemented a scientific and editorial quality review procedure whereby expert consultants from outside the National Library of Medicine (NLM) conduct an independent review of journals seeking to participate in PMC. This was in response to a significant increase in new publishers and journals applying to participate in PMC, many of which are unknown to NLM in terms of quality and publishing practices. The independent review, which was approved by the PMC National Advisory Committee (see minutes from June 10, 2014), follows an assessment by NLM that the journal meets NLM's criteria for its collection, as outlined in the Collection Development Manual.

PMC also recently updated the minimum requirement on the number of substantive, peer-reviewed articles needed before a journal can apply to PMC. The new 25-article minimum ensures that the reviewers have a sufficient amount of content on which to base their recommendation for inclusion in PMC. The new minimum article requirement takes effect on January 1, 2016. Publishers are encouraged to use the 25-article minimum as a guideline in the interim when submitting applications.

November 23, 2015

CC0 Filter Now Available

PMC includes some journals published by US government agencies that make their articles available under a Creative Commons CC0 (public domain) license. Some other journals also apply a CC0 license to selected articles in PMC. All these articles may be used and reproduced without special permission. However, anyone using the material is requested to properly cite and acknowledge the source.

You may now search for CC0 articles by using special filters in both PMC (cc0 license[filter]) and PubMed (pmc cc0 license[filter]). These filters are based on license information that is provided to PMC by publishers and encoded as machine-readable identifiers in the source XML of each article. For more information, see the FAQ titled How do I search for articles by Creative Commons license? page.

Please bear in mind that these articles, although made available under a CC0 license, may still contain photographs or illustrations copyrighted by other commercial organizations or individuals that may not be used without obtaining prior approval from the holder of the copyright.

February 05, 2015

Full text now available for OA subset articles, in plain text format

In order to facilitate text and data mining for articles in the Open Access Subset, we are now providing plain text files for those articles on our FTP site. These files contain the full text of the article, extracted either from the XML source files, or (for those articles that don't have XML) the PDF files. Users are directly and solely responsible for compliance with copyright restrictions and are expected to adhere to the terms and conditions defined by the copyright holder (see the PMC Copyright Notice).

These text files are bundled in gzipped archives. Note that these files are quite large (each greater than one gigabyte). They are available for download as:

These files are updated every week, on Saturday.

For more information, see the Bulk Packages of OA Articles section of our FTP Service page.

November 18, 2014

Citation Exporter Feature Now Available

PMC is happy to announce the addition of a citation exporter feature. This feature makes it easy to retrieve either styled citations that you can copy/paste into your manuscripts, or to download them into a format compatible with your bibliographic reference manager software.

When viewing an Entrez search results page, each result summary will now include a "Citation" link. When, clicked, this will open a pop-up window that you can use to easily copy/paste citations formatted in one of three popular styles: AMA (American Medical Association), MLA (Modern Language Association), or APA (American Psychological Association). In addition, the box has links at the bottom that can be used to download the citation information in one of three machine-readable formats, which most bibliographic reference management software can import.

The same citation box can also be invoked from an individual article, either in classic view (with the "Citation" link among the list of formats) or the PubReader view, by clicking on the citation information just below the article title in the banner.

These human-readable styled citations, and machine-readable formats, will be available through a public API, and we will be providing more details about that in another announcement, on the pmc-utils-announce mailing list. Please subscribe to that list if you are interested.

March 28, 2014

PMC Advisory Committee Meeting to be Held in June

This year's PMC Advisory Committee meeting will be held on Tuesday, June 10. The meeting will take place in the NLM Board room starting at 9:30 am. Stay tuned for further details.

February 24, 2014

Three Million Articles are Now in PMC!!

As of February 21, 2014, PMC became home to three million articles! As listed on our home page, the content has been provided in part by 1441 full participation journals, 277 NIH Portfolio journals and 2470 selective deposit journals. For related information on PMC milestones, see these announcements from 2007 and 2010, respectively.

November 18, 2013

PMC Releases New ID Converter

PMC has just released an upgrade to our ID converter, now dubbed the PMCID - PMID -Manuscript ID - DOI Converter. This utility allows you to start with the unique identifier for an article that is in PMC, and find additional unique identifiers that may apply to the article. Improvements include support for DOIs, auto-detection of the ID type based on its format, and enhanced output. It also provides output in any of several different formats: HTML, XML, JSON, or CSV. This tool uses an underlying web service, that is also publicly available for those needing programmatic access to this data. See the ID Converter API documentation.

November 18, 2013

New Version of NCBI Handbook is Released

The NCBI Handbook, 2nd Edition was released on November 14 and is now searchable in Bookshelf. The handbook features an updated section on PMC, which includes information on article retrieval, data processing, and PMC tools and utilities. Other PMC-related literature sections that have been updated include Bookshelf, the NIH Manuscript Submission System and the NLM DTD.

September 04, 2013

New Version of PubReader is Released

PMC has recently released an updated version of its PubReader view. The new version (1.2) includes a "search this page" feature that allows you to find specific terms within the article. The latest source code is also available from the GitHub repository.

August 15, 2013

A New PMC Mailing List and RSS Feed

PMC has recently replaced the PMC-News mailing list and its accompanying RSS feed with a new PMC-Announce list and a new RSS feed. Please note that the older list and feed have now been retired. To subscribe to the new announcement list, see https://www.ncbi.nlm.nih.gov/mailman/listinfo/pmc-announce/. To see the new RSS feed, update your news reader to subscribe to https://www.ncbi.nlm.nih.gov/pmc/about/new-in-pmc/?format=rss.

August 05, 2013

Search for Open Access Articles by License

You can now search for Open Access articles that have certain types of licenses, by using special filters in both PMC and PubMed. These filters are based on license information that is provided to PMC by publishers and other content providers, as encoded by machine-readable identifiers in the source XML of each article. For more information, see our FAQ titled How do I search for articles by Creative Commons license?.

July 17, 2013

JATS-Con 2013 Program is Now Available

JATS-Con is a conference for users of the Journal Article Tag Suite, that is, users of any of the "NLM DTDs" or NISO Z39.96. JATS-Con will take place on the NIH campus in Bethesda, Maryland on October 22 and 23, 2013.

The full program is now available, as are proceedings from previous years.

There is no charge for the conference; however, space is limited so registration is required.

You may also sign up for a pre-conference tutorial on October 21, 2013. Details are on the Tutorial Registration page.

April 22, 2013

Keep Better Track of PMC Features

PMC has created a new email list for announcements of new or updated tools and utilities to help you keep better track of improvements to the archive. To find out more information about the list, or to subscribe, please visit PMC-Utils-Announce.

April 19, 2013

New OA Web Service for PMC

PMC is pleased to announce the new OA web service, designed to allow tool developers an easier way to find content in the PMC open access subset. Until now, it has not been easy for outside users to determine which articles in the subset are new or have been updated recently. Our new OA web service addresses this need. It provides a simple API to allow you to query the subset, to find PDF or tgz (tarred-gzipped) format files, either by article ID, or by date/time ranges. More information, along with examples, is available from the documentation page, at OA Web Service. Your feedback is welcome; please send it to the PMC Help Desk, at pubmedcentral@ncbi.nlm.nih.gov.

February 01, 2013

KoreaMed Synapse Adds PubReader as a Display Option

KoreaMed Synapse, a digital archive and reference linking platform of Korean medical journals, is now using NCBI's new PubReader presentation style to display their full-text journal articles. KoreaMed's database of 122 journals now includes a blue 'PubReader' icon for each full-text article. NCBI launched PubReader in December 2012 as a convenient new way to view full-text articles in PubMed Central on desktops as well as tablets and mobile devices. In tandem with the launch, NCBI made the code used to create PubReader freely available on GitHub.

February 01, 2013

PMC Advisory Committee Appoints New Members

As of February 1, 2013, the following new members have been appointed to serve on the PMC National Advisory Committee: Ms. Sharon Terry of the Genetic Alliance; Dr. C. Victor Jongneel of the University of Illinois at Urbana-Champaign; Dr. Bevin Engelward of the Massachusetts Institute of Technology; Dr. Randall Morse of the Wadsworth Center; and Dr. Adelita Cantu of the University of Texas. For more information, see PMC National Advisory Committee.

December 11, 2012

PubReader - A New Presentation Style for PMC

NCBI has developed a new web presentation style called PubReader, which offers you an easier way to use your Web browser to read the articles in PMC. Designed particularly for enhancing readability and navigation on tablet and other small screen devices, PubReader can also be used on desktops and laptops and from multiple web browsers. For more information on PubReader, see the article in the November-December issue of the NLM Technical Bulletin.

November 05, 2012

UKPMC Rebranded as Europe PMC

With the addition of several European sponsoring agencies, including the European Research Council, UKPMC was renamed Europe PMC as of November 1, 2012. Europe PMC is an outgrowth and expansion of UKPMC, which was first launched in January 2007 with sponsorship from the Wellcome Trust and several other funders of biomedical research in the UK. Europe PMC receives all of its final published articles directly from the U.S. PMC archive. It also accepts and processes author manuscripts of journal articles funded by the Europe PMC sponsoring agencies and makes them available to U.S. PMC and PMC Canada. For more information, see PMC International.

August 22, 2012

JATS Becomes NISO Standard

The Journal Archiving Tag Suite(JATS), known formerly as the NLM DTD, has now been officially adopted as an American National Standards Institute (ANSI)/ National Information Standards Organization (NISO) standard. According to the press release from NISO, "JATS provides a common XML format in which publishers and archives can exchange journal content by preserving the intellectual content of journals independent of the form in which that content was originally delivered." For more information, see NISO Publishes Journal Article Tag Suite (JATS) Standard.

July 13, 2012

A Facelift for PMC

PMC has recently undergone another redesign to improve the look and feel and functionality of the site, featuring more white space, cleaner lines and enhanced navigation on its article, issue, and journal archive pages. For more information, see the article in the July-August 2012 issue of the NLM Technical Bulletin.

July 12, 2012

New Version of PMC Help is Released

The PMC user's guide, PMC Help has been updated to include new and improved information on navigating the site as well as descriptions and instructions on using the new search functions, such as Limits and Advanced Search Builder. Further updates will also be forthcoming.

March 26, 2012

JATS-Con Dates Announced for 2012!

The third annual Journal Article Tag Suite Conference (JATS-Con) will be held on October 16 and 17, 2012 on the NIH Campus in Bethesda, Maryland. JATS-Con is a conference for users of the NISO Z39.96 Journal Article Tag Suite: that is, users of any of the NLM DTDs. JATS-Con is a peer-reviewed conference with a broad range of content on the Tag Suite from the technical to publishing theory — and the latest news on the Tag Suite. For more information, see JATS-Con.

February 29, 2012

PMC Advisory Committee Appoints New Members

The following new members have been appointed to serve on the PMC National Advisory Committee: Martha Bedard, Dean of Libraries at the University of New Mexico; and Lorraine Haricombe, Dean of Libraries at the University of Kansas and a member of SPARC's board. The next meeting of the committee is scheduled for June 19, 2012. For more information, see PMC National Advisory Committee.

July 12, 2011

JATS-Con is Coming!

The second annual Journal Article Tag Suite Conference (JATS-Con) will be held on September 26 and 27, 2011, at the Natcher Conference Center on the NIH Campus in Bethesda, Maryland. The 2011 conference will feature a host of presenters who will discuss topics ranging from Best Practices to PMC Tagging Guidelines. For more information on the conference and the program, see JATS-Con.

June 20, 2011

The PMC 10th Anniversary Video is now on YouTube!

A video celebrating PMC's first decade is now available for viewing on the NCBI YouTube Channel. The PMC 10th Anniversary Video can also be found on the regular YouTube site.

June 14, 2011

PMC Advisory Committee to Meet at NLM

The PMC Advisory Committee will hold its annual meeting at the National Library of Medicine on Friday, June 17, 2011 from 9:30 am to 3 pm. Four new committee members will be joining the group, see New Members Appointed to PMC Advisory Committee. Presentations will include discussions relating to the NIH Public Access policy and a viewing of the PMC 10th Anniversary video. For more information, see PMC National Advisory Committee.

May 26, 2011

A Brand New Look for PMC!

PMC has gotten a facelift-- or more accurately, an interface-lift! The home page, search page and other PMC informational pages have all undergone an overhaul, in order to provide users with easier navigation, enhanced features, and a look and feel that is more consistent with other recently updated NCBI sites, such as PubMed and Bookshelf. Additional new features and updates will be coming soon. For more information on navigating the new site, see the article in the July-August issue of the NLM Technical Bulletin.

February 28, 2011

Ten Years After: PMC Milestone Featured in

PMC marked its 10th anniversary in 2010 with a celebratory event at its annual Advisory Committee meeting, held at the National Library of Medicine last June. This milestone event was recently featured in the February 17th edition of NLM In Focus, in an article NLM Milestones: The Hits Just Keep on Coming. For more information on the ten years of PMC, see the article in the May-June issue of the NLM Technical Bulletin.

February 17, 2011

New Members Appointed to PMC Advisory Committee

Four new members have been appointed to serve on the PMC National Advisory Committee: Philip Bourne, of the University of California, San Diego; Sophia Colamarino, an independent consultant in San Francisco; Paul Courant, of the University of Michigan; and Patricia Thibodeau, of Duke University. Each member will serve a 4-year term. The next meeting of the committee is scheduled for Friday, June 17, 2011. For more information on the committee, see PMC National Advisory Committee.

September 14, 2010

A New Look and Feel for PMC's Public Access Page

The Public Access & PMC page has been redesigned for greater clarity and usability. In addition to including a list of the FAQs at the top, the new page features a table illustrating all the ways to find various reference numbers for an article: the PMID, NIHMSID, and most important, the PMCID, which must be used to demonstrate compliance in terms of the NIH Public Access Policy.

June 25, 2010

PMC Hits Two Million Mark!!

It's official—PMC has just become home to two million articles! The record-breaking article, which came from the American Journal of Medical Genetics Part B: Neuropsychiatric Genetics, became publicly available in the PMC archive on June 23. This new PMC milestone has occurred almost three years to the day since PMC reached its last one: the one-million article mark in June 2007. See also: PubMed Central Hits One Million Article Mark.

June 17, 2010

First-Ever Journal Article Tag Suite Conference (JATS-Con) to be Held in November 2010

PMC is pleased to announce the first of what we hope will be an annual series of conferences for users of the Journal Article Tag Suite, that is, for users of any of the “NLM DTDs”. The Journal Article Tag Suite Conference (JATS-Con) is a peer-reviewed conference that will feature a broad range of content on the Tag Suite—from the technical components to publishing theory—as well as the latest news on the Tag Suite. The conference will be hosted by the National Center for Biotechnology Information (NCBI) at the National Library of Medicine on the NIH campus in Bethesda, Maryland on November 1 & 2, 2010.

For more information on the conference, see https://jats.nlm.nih.gov/jats-con.

Note: There is no charge for the conference; however, space is limited so preregistration is required.

April 29, 2010

PMC Canada's Manuscript Submission System Goes Live!

The PMC Canada manuscript submission system was released on April 28, 2010. The system will enable researchers funded by the Canadian Institutes of Health Research to deposit their peer-reviewed research publications, in compliance with CIHR's Policy on Access to Research Outputs.

February 24, 2010

New Members for PMC Advisory Committee

Four new members have been appointed to serve on the PMC National Advisory Committee: Mike Rossner of Rockefeller University Press, Jan Fassler of the University of Iowa, Ivy Anderson of the California Digital Library, and Delores Meglio from the Knovel Corporation. Each member will serve a 4-year term. The next meeting of the committee is scheduled for June 4, 2010. For more information on the committee, see PMC National Advisory Committee.

November 16, 2009

New URLs in PMC

PMC recently redesigned its URL format to allow for easier usability as well as consistency across the NCBI site. To implement this change, we moved the previous site, www.pubmedcentral.nih.gov, into the NCBI domain as a sub-site. You can now access the PMC home page at https://www.ncbi.nlm.nih.gov/pmc.

The primary advantage of the new format is to enable the PMC site to become more fully integrated with other NCBI resources. The new URLs are also more user-friendly—they no longer include technology-driven terminology, such as CGI script names and file extensions (Figure 1).

Figure 1 - Old URL for Journal Page with CGI Script Name

Instead, note that after the NCBI/PMC address, the URL first identifies the type of resource, e.g., the PMC journal list, with subsequent identification for a particular subset of that resource—in this case, the journal number (Figure 2).

Figure 2 - New URL for Journal Page with Journal Number

Additionally, you will have greater flexibility in accessing particular types of material because, in a number of cases, more than one URL can be used for the same resource. In these instances, one URL is considered to be canonical, or primary; however, using any of the ancillary URLs for that resource will redirect you back to the canonical one. For example (see Figure 3), although the first URL, which represents the PMCID, is considered to be the canonical URL, you may also access the article by using other identifiers, such as the pmid, doi, or the issn-volume-issue-page (ivip).

Figure 3 - Canonical and Ancillary URLs for the Same Full-Text Article

Finally, with the roll-out of these more stable and standardized URLs, as in the table below (Figure 4), you will also find it easier to modify the web addresses in your browser. Note that the canonical URL is given first and is in bold; the ancillary URLs are listed below it.

Figure 4 - Table Display of all New URLs

Although the new URLs are firmly in place, please also note that we haven't completely discarded the old to bring in the new. If you do use an old URL, it's not a problem. Your browser will be redirected to the new location.

October 28, 2009

PMC Now Offers a "Preview" Table of Contents for Embargoed Issues

For any journal issue that has at least one open access or early access article, PMC is now displaying the table of contents (TOC) in advance of the whole issue becoming available. Not to worry, though—only those articles specified for early release are immediately viewable in PMC. As consistent with the terms of access in the journal agreement, the other articles will only become available on their specified release date, as shown in the TOC below.

The journal's accessiblity, as indicated on the PMC Journal list also has not changed; for example, Plant Physiology's embargo period is still 12 months. What has changed is that the issues with "preview" TOCs now additionally appear on the journal's archive page. Publishers and others can rest assured, however, that no access terms for any journal have been changed with the unveiling of this new format.

October 21, 2009

PMC Canada is Launched!

The newest addition to the PMC International effort, PubMed Central Canada has now been made public. Stay tuned for the launch of PMC Canada's manuscript submission system later this year.

October 01, 2009

PMC Adds New Page on Public Access

A new page, Public Access & PMC, has now been added to the About PMC section of the PubMed Central site. “Public Access & PMC” provides information on the relationship between PMC and the NIH Public Access policy, including the difference between the NIH Public Access journal list and PMC journal list. In particular, authors and publishers should find this new site to be a useful resource.

July 24, 2009

New Search Function Released

You can now find embargoed articles and their corresponding PMCIDs through a recently released search option in the PMC Entrez database. Using the "Limits" tab, click in the field, "Show both free and embargoed articles" and refine your search by journal, author, date, article type, and/or tag term, as needed. Once you're on the summary page, click on the "embargoed" tab at the top to find the articles in this category. You can then find the PMCID and date of availability at the bottom of the article citation, as indicated in the example below. Note: The PMC search option only includes articles with an initial embargo of up to 12 months. Articles with an embargo greater than 12 months are not compliant with the NIH Public Access Policy and will appear in search results only when the full text is free in PMC. For more information, see the article in the September-October issue of the NLM Technical Bulletin.

July 06, 2009

PMC Canada to Start in Fall 2009

Canada is soon expected to join the international effort to provide access to health research through the PMC International network of digital archives. PMC Canada is the result of a three-way collaborative effort by the National Library of Medicine (NLM), the Canadian Institutes of Health Research (CIHR), and the National Research Council's Canada Institute for Scientific and Technical Information (NRC-CISTI). Similar to UK PubMed Central, PMC Canada will include most of the health and life sciences literature available through the U.S. PMC. PMC Canada will also include research resulting from funding through the Canadian Institutes of Health Research (CIHR). Components of the new repository will include a bilingual interface as well a manuscript submission system for CIHR researchers.

June 16, 2009

PMC Advisory Committee Meets at NLM

The most recent meeting of the PMC Advisory Committee was held at the National Library of Medicine on June 15, 2009. The committee meets at least once a year and its members are appointed by the NIH Director from the biomedical information communities and the general public. Dr. Gary Ward, of the Department of Microbiology & Molecular Genetics at the University of Vermont, has been appointed to serve as Chair of the Committee through January 2011.

May 19, 2009

New Version of PubMed Central Journal List Released

PMC released a new and improved journal list on March 31, 2009, after a comprehensive redesign for greater clarity and organization.

The new design not only combines the full-list and tabbed-list views of the previous version but also includes some new or updated features to provide users with a greater overview of the total PMC archive. Looking at this new list, you will find:

An Expanded View of PMC journals that includes NIH Portfolio
Special Collections
A New "Participation Level" Journal Category
Hide/Show Display Option for Predecessor Titles
Article and Journal Search Feature

For more information, see the complete article in the May-June issue of the NLM Technical Bulletin: https://www.nlm.nih.gov/pubs/techbull/mj09/mj09_pmc_redesign.html