PubMed is a project developed by the National Center for Biotechnology Information (NCBI) at the National Library of Medicine (NLM), located at the National Institutes of Health (NIH). It has been developed in conjunction with publishers of biomedical literature as a search tool for accessing literature citations and linking to full-text journals at Web sites of participating publishers. MEDLINE (MEDlars onLINE) is the National Library of Medicine's (NLM) premier bibliographic database covering the fields of medicine. PREMEDLINE was introduced by the National Library of Medicine in August 1996 and is a database which provides basic citation information and abstracts before the full records are prepared and added to MEDLINE.