Academic Search Premier
The world's largest academic multi-disciplinary database. Includes full text access to over 4,000 scholarly (peer-reviewed) publications back to 1975. A great place to start your research on any topic. Find search tips on their help page.
Sources Indexed: http://www.epnet.com/titleLists/ap-fulltext.htm
Coverage: Coverage varies, some starting with 1975 - present, updated continuously.