Books can provide an in-depth look at a topic, and are often written in a style that explains and contextualizes a phenomenon more. If using books is allowed by your professor for a research paper, this can be a good option for students. Remember, you won't be reading the whole book, just the portions that apply to your research.
Tips for Searching:
Once you've run a search, use the "Refine My Results" options on the left side of the page. It's a quick way to drill down to the most useful results without paging through a lot of items you're not really interested in. Options often include: