There are a couple of ways actually: you can select a subject area from our LibGuides on the right side of the Library's homepage (http://sru.libguides.com). From there select a database to start searching, choosing one or two (or three) keywords to get started.
Another option is to use the A-Z database list (http://sru.libguides.com/az.php) to select a particular database. You did not mention your topic, so I'm not sure where to point you, but Academic Search Complete is a good general database.
Let us know if you get stuck! Good luck!