These databases primarily provide biographical information, though many subject-specific databases will have biographical entries (look for limiting-options on their advanced search screens).
American National Biography provides HTML full-text biographical entries and over 2,700 illustrations on 18,700 men and women -- from all eras and walks of life -- whose lives have shaped the nation. It includes access to The Oxford Companion to United States History encyclopedia with entries on all aspects of American history.
People Search includes biographies from reference and news sources, including historical and political figures, entertainers, deceased people featured in various Who's Who publications, and people profiled in major news publications within the last two years. 1985-present, plus a retrospective of major 20th century people.
MasterFILE Premier indexes citations, abstracts, and full-text articles, books and reference works (including the World Almanac, American Heritage Dictionary, and Book of Facts), primary source documents, photos, maps, flags, biographies, book reviews from Magill Book Reviews, and news transcripts. Full text available in HTML, PDF, and some scanned image formats. You can limit to peer-reviewed sources.
American Men & Women of Science provides full-text biographical entries in HTML and PDF of living persons in the physical and biological fields, as well as public health scientists, engineers, mathematicians, statisticians, and computer scientists.