A DOI (digital object identifier) is a unique alphanumeric string assigned to a digital object such as an electronic journal article, a conference paper or a book chapter. A DOI uniquely identifies the content item and provides a persistent link to its location on the internet. Look for the DOI as part of reference lists or citations. If you know the DOI of a paper (looks like this: doi:10.1007/s10067-006-0283-5), you can find the paper using a DOI Resolver.
Web of Science is a comprehensive citation tracking database with coverage from 1900 to the present. It provides thorough coverage of ~5900 major journals. Includes cited author searching. Abstracts, keywords, and additional subject categories are included and searchable from 1991+. (Video Tutorial)
A detailed guide covering all features of Web of Science is available to show you step by step how to keep track of the research conducted in your field or of citations to your papers.
International coverage of journal articles, selected web sites, and patents in the sciences and social sciences; provides citation tracking for journal articles and conference papers from 1996 to the present.
Medline (PubMed) - A National Library of Medicine database, covers more than 4000 journal titles and is international in scope. Abstracts, keywords, and MESH subject categories are included and searchable from 1950+.
BIOSIS Previews - With more than 13,000,000 records from publications in over 90 countries, Biosis Previews is the most comprehensive index of journals, meetings, conferences, and symposia in the life sciences. Although this is not a full-text article database, our PULinks system conveniently links you to the full-text. Coverage from 1926+
Reaxys - Detailed index of inorganic and organometallic chemistry. Fully searchable by structures, substructures, and reactions. From 1772+.