To Search Individual Databases:
PsycINFO (EBSCO) - contains millions of citations and summaries of journal articles, book chapters, books, dissertations and technical reports, all in the field of psychology and related fields. Limit to "empirical study."
ScienceDirect (Elsevier) - offers access to large amounts of high-quality, peer-reviewed journal articles online, complemented by authoritative reference works.
Web of Science (Thomson) - Citations for all sciences going back to roughly the 1950's. Connects articles and research through citations in bibliographies of articles.
For Comprehensive Search:
Omnisearch - search most of the library's databases via the EBSCOhost interface.
Make sure to limit to Scholarly (peer-reviewed) journals
KU's Google Scholar - search scholarly content using Google search. Using KU's authenticated Google Scholar link will link you to any full-text available via library resources. If you have a Gmail account you can save citations to MyLibrary in Google Scholar.