The National Library of Medicine's free article search engine, containing article references from MEDLINE, PreMEDLINE, OLDMEDLINE, plus publisher-supplied and out-of-scope citations from science and chemistry journals.
Database with abstracts and citations of research literature and quality web sources, including journals, conference proceedings, trade publications, abstracts, and patent records. A multidisciplinary resource covering materials from the humanities, sciences and social sciences. Also indexes EMBASE and allows you to locate the most highly cited items and the articles that cite them.
Web of Science indexes thousands of scholarly journals, books, reports, conferences and more. Citation information and analysis with cited reference searching available. The collection includes Science Citation Index Expanded (1990-present), Social Sciences Citation Index Expanded (1990-present), Arts & Humanities Citation Index (1990-present), Conference Proceedings Citation Index (1990-present), Book Citation Index (2005-present), Current Chemical Reactions (1985-present) and Index Chemicus (1993-present).