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Articles available from the PMC site are provided by the respective publishers or authors. Articles in PMC usually include an explicit copyright statement. To see the details for any given record, see the “Copyright and License information” link on an article record. In the absence of a copyright statement, users should assume that standard copyright protection applies, unless the article contains an explicit statement to the contrary. In case of doubt, contact the journal publisher to verify the copyright status of an article.

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PMC makes certain subsets of articles (i.e., the PMC Article Datasets) accessible through auxiliary services that may be used for automated retrieval and downloading. These are:

These services are the only services that may be used for this purpose. Do not use any other automated processes for downloading articles, even if you are only retrieving articles from the PMC Article Datasets (including the PMC Open Access Subset).

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.,

Articles published in these journals are in the public domain and may be used and reproduced without special permission. However, anyone using the material is requested to properly cite and acknowledge the source.

Please note open access and public domain articles 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.

Author Manuscripts

Author manuscripts added to PMC in compliance with a funder policy often do not include copyright statements or license terms. Authors own the original copyrights to materials they write. Consistent with individual arrangements with authors' employing institutions, authors often transfer some or all of these rights to the publisher when the journal agrees to publish their paper. Some publishers may ask authors to transfer these rights when the paper is first submitted to the journal. Journal-level policy details may be available from the publisher’s website.

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

Articles added to PMC as part of a digitization project often do not include copyright statements. Users should assume that standard copyright protection applies, unless the article contains an explicit statement to the contrary.

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.

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Last updated: Wed, 7 Jul 2021