Science Citation Index / Science Citation Index Expanded is a database that lists published articles from approximately 6,000 major scientific, technical and medical journals and links them to the articles in which they have been cited (a feature known as cited reference searching). It is available online as SciSearch and on the internet as Web of Science. Web of Science is also incorporated in Web of Knowledge. It can be searched as a source database like MEDLINE. It can also be used to identify studies for a review by identifying a known relevant source article, and checking each of the articles citing the source article, to see if they are also relevant to the review. It is a way of searching forward in time from the publication of an important relevant article to identify additional relevant articles published since then. Records also include the listed references from the original record, which in turn are another possible source of relevant trial reports. Citation searching is an important adjunct to database searching and handsearching (Greenhalgh 2005). Information about these products is available at:
o scientific.thomson.com/products/sci/
o scientific.thomson.com/products/wos/
A similar database exists for the social sciences known as Social Sciences Citation Index:
o scientific.thomson.com/products/ssci/
In 2004, Elsevier launched an abstract and citation database - Scopus. Scopus covers 15,000 journals (of which over 1,200 are open access journals) and 500 conference proceedings. It contains over 33 million abstracts and results from nearly 400 million scientific web pages:
o info.scopus.com/overview/what/