When starting your search it's important to do two things:
To do this start with a general purpose database to help you develop your search terms. After you have your search terms developed you can move onto one of the subject databases on the the Science and Technology or Social Science and Humanities pages.
Scholarly databases contain journal articles, book chapters, conference proceedings, meeting reports, and more.
If your topic is "hot" or one that sparks debate and strong feelings, then you might want to check these specialty databases.