Google Scholar - Stand on the shoulders of giants (Tracking is 'free')

Indiana University - Digital Library of the Commons

Check out the DLC to find international literature including free and open access full-text articles, papers, and dissertations.

Infomine - UC Riverside LIbrary

The Infomine is an incredible tool for finding scholarly Internet resource collections, especially in the sciences.

Internet Public Library

Find resources by subject through the Internet Public Library’s database.

Microsoft Academic Search

Microsoft’s academic search engine offers access to more than 38 million different publications, with features including maps, graphing, trends, and paths that show how authors are connected.