MEDLINE is the United States National Library of Medicine's premier bibliographic database providing information from the following fields: Medicine, Nursing, Dentistry, Veterinary medicine, Allied health, Pre-clinical sciences. The MEDLINE database is the electronic counterpart of Index Medicus, Index to Dental Literature, and the International Nursing Index. The Ovid MEDLINE database contains bibliographic citations and author abstracts from more than 5,500 biomedical journals published in the United States and in 70 other countries. The database contains over 13 million citations dating back to 1950, and is updated daily.