PubMed Central® (PMC) is a free archive of biomedical and life sciences journal literature at the U.S. National Institutes of Healths National Library of Medicine (NIH/NLM). In keeping with NLM’s legislative mandate to collect and preserve the biomedical literature, PMC serves as a digital counterpart to NLM’s extensive print journal collection. Launched in February 2000, PMC was developed and is managed by NLM’s National Center for Biotechnology Information (NCBI).

Scopus is an abstract and citation database of peer-reviewed research literature, indexing over 19,000 titles from more than 5,000 international publishers. Scopus covers the scientific, technical, medical and social sciences fields as well as arts and humanities. Scopus includes scholarly journals, book series, conference proceedings, trade publications and Open Access journals. It also provides metrics and analytical tools. A detailed user guide is available on the Scopus LibGuide

Web of Science provides authoritative, multidisciplinary content covering over 12,000 of the highest impact journals worldwide, including Open Access journals and over 150,000 conference proceedings. Youll find current and retrospective coverage in the sciences, social sciences, arts, and humanities, with coverage to 1900.Searching across the Science Citation Expanded®, Social Sciences Citation Index®, Arts & Humanities Citation Index™, Conference Proceedings Citation Index - Science, and Conference Proceedings Citation Index - Social Science & Humanities, Emerging Sources Citation Index and Preprint Citation Index in one search interface.