Bookshelf This link opens in a new windowMaintained by the National Center for Biotechnology Information, Bookshelf is a growing collection of full-text biomedical books that can be searched directly by typing a concept into the textbox on the site. Subjects covered by its books include health care, evidence-based medicine, health policy, comparative effectiveness research, and public health. It is also accessible under "Books: Online Books" through the Entrez site.