PubMed This link opens in a new window Free (non-subscription) access to the National Library of Medicine's MEDLINE and PreMEDLINE. MEDLINE encompasses information from Index Medicus, Index to Dental Literature, and International Nursing Index, as well as other sources of coverage in the areas of allied health, biological and physical sciences, humanities and information science as they relate to medicine and health care, communication disorders, population biology, and reproductive biology.