These sources can help you identify or narrow a topic, provide reliable background information in order to gain a general overview of a topic, and provide context.

AND both terms must be present:  crime AND women

OR either term may be present:      women OR females 

* finds characters beyond the root word (some databases have other symbols)
  communit* will search for community as well as communities

Pay attention to subject terms or descriptors located in article databases.  These terms will give you ideas for other keywords.  Sometimes less is more.  If your search has a lot of aspects to it, focus on a few of the most important concepts.