NCBI is part of the National Library of Medicine (NLM) at the National Institutes of Health (NIH). NCBI advances science and public health by providing free access over the Internet to biomedical literature and genomic data, making it one of the 400 top most-visited sites in the world. NCBI has a diverse staff of smart, talented, and deeply technical people who collaborate to build critically valuable services for researchers, physicians, educators, students, and the general public. For example, NCBI develops and delivers PubMed, an index of over 29 million biomedical research abstracts; and maintains ClinicalTrials.gov, a database of over 400,000 clinical studies around the world.