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.
Open protocol repositories
