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Open Access Articles
Articles that are "open access" in PMC are made available under a Creative Commons or similar license that allows more liberal redistribution and reuse than a traditional copyrighted work. Many articles in PMC are protected by U.S. and/or foreign copyright laws, even though PMC provides free access to it. Some journals use the label "open access" for an article that is available free at time of publication, but is still subject to traditional copyright restrictions.
Open access articles are included in the PMC Open Access Subset and can be found in PMC by searching open access[filter]. This subset also includes a number of U.S. government publications, e.g.,
- Addiction Science & Clinical Practice (vol. 1 through vol. 6)
- Alcohol Research: Current Reviews
- Emerging Infectious Diseases
- Environmental Health Perspectives
- Journal of Research of NIST
- Morbidity and Mortality Weekly Report
- Preventing Chronic Disease
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Public Health Emergency COVID-19 Initiative Articles
The license for each article deposited in PMC under the Public Health Emergency COVID-19 Initiative is at the discretion of the individual publishers and scholarly societies who deposit them. In some cases, articles are made available for reuse under a Creative Commons license (generally, CC BY). Articles that do not have a Creative Commons license will include a custom license that allows for the article to be made available via the PMC Open Access Subset for re-use and secondary analysis with acknowledgement of the original source for the duration of the public health emergency. This subset is referred to as the PHE Timebound Article Dataset.
As with all PMC Open Access Subset content, the license terms on these articles, including those with custom licenses, are not all identical. Please refer to the license statement in each article for specific terms of use.
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PMC provides long-term preservation of author manuscripts and makes them available free to read, text mine, and for other uses consistent with the principles of Fair Use.
Digitized Articles
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Some of the digitized articles are distributed under a Creative Commons license and note that in the article record. Those that are covered by a Creative Commons license are included in the PMC Open Access Subset.
Digitized articles that are in the public domain carry a statement indicating that they are free from known copyright as described by the Creative Commons Public Domain Mark 1.0. These articles are also included in the PMC Open Access Subset.