CINAHL and Medline are two major health science databases. CINAHL focuses on nursing and allied health fields, containing articles from 750 journals and over 1 million citations dating back to 1937. Medline is a broader medical and health science database containing articles from over 4,800 journals and 19 million citations dating back to 1940 covering many health fields including medicine, nursing, and allied health. Both CINAHL and Medline are comprehensive sources for searching health science literature.