PubMed Central

PubMed Central is a free open access online database of scientific papers. It grew from the online Entrez PubMed biomedical literature search system. PubMed Central was developed by the U.S. National Library of Medicine as an online archive of biomedical journal articles. The full text of many articles is available for free. Some participating journals still charge for access to recent (often the latest 6 months) articles.

See Medline for more information.