Specialized encyclopedias, handbooks, guides, and other reference works can get you started by defining specialized terms or the scope of an issue or problem. They often give a good overview of a broad topic, such as "domestic violence," summarizing the scholarly research and leading you to further sources within the article or in the bibliography.
The Gale Virtual Reference Library database has sociology related reference books available electronically. Using subject encyclopedias for background information can be very helpful as you begin research in a new area because they will give you a historical perspective and a sense of your topic's scope.
A specific title to try in Gale Virtual Reference Library: International Encyclopedia of the Social Sciences, 2008.
The Ebrary and EBSCO EBook databases have a large number of e-books in the field of sociology. You can read online or print out pages from the books.