Start with a keyword search. Keyword searches look for your terms in the title, author, description, and subject fields.
To find only books on the topic, Refine Results to books in the left column. 
If you do not get any (or enough) results, your search might be too narrow or you might be entering too many terms (example: cigarette, smoking, health, teenagers, effects). Try to broaden your search by entering only one or two key concepts (smoking, teenagers).
If you get too many results, try to add terms to your search to explore a more specific aspect. For example, a search for "violence" produces over 10,000 results. Adding "media" produces still over 600 results. Searching "violence" "media" and "gender" together narrows the results to a (more) manageable number.
If you find books that might be useful, look at the subjects listed in the Details tab. Those subjects can be used to find more books on your topic.