In 2001, just 7% of the articles published in that year and added to UKPMC, were defined as "open access". [35,061 articles, with a publication year equal to 2001, were added to UKPMC, of which only 2,543 were open access.]
In 2009, 33% of the articles published that year and added to UKPMC were classified as "open access". [125,592 articles, with a publication year equal to 2009, were added to UKPMC, of which 41,811 were fully open access.]
The graph below shows the growth of open access articles in UKPMC between 2001 and 2009.
|Open access articles in UKPMC: 2001 and 2009|
Open access articles are still protected by copyright, but are made available under a Creative Commons or similar license that generally allows more liberal redistribution and reuse than a traditional copyrighted work.
Crucially, because these articles can be downloaded without restrictions, users can deploy text mining tools to crawl this corpus of literature to help identify new facts and knowledge.
The open access articles in UKPMC can be downloaded from the UKPMC FTP site. This site is updated weekly.