The National Library of Medicine free article search engine, containing article references from MEDLINE, PreMEDLINE, OLDMEDLINE, plus some publisher-supplied and out of scope citations from certain general science and chemistry journals. To run a cited reference search on an article found in PubMed, copy and paste the PMID article Identifier here.
SciFinder Scholar contains a comprehensive database of chemical and chemical engineering literature including patents (1907 - date, with selected coverage back to 1878) and the CAS Registry with information on 18 million substances. Also useful for biotechnology, toxicology, environmental science, medicine, food science and nuclear science.
Compendex indexes technical and engineering journals, conference proceedings and papers, technical reports, and monographs. Subjects include all areas of engineering; transportation; management, mathematics, and physics; electronics and communications; computers and data processing, and instruments and measurements.
Enter a PMID (PubMed Identifier) number to find times cited information in Scopus. PMIDs can be copied and pasted from UpToDate, AccessMedicine, and other online textbooks. Scopus includes cited references primarily for articles published after 1996.