People use Google and Wikipedia to introduce themselves to unfamiliar knowledge. Both are inadequate, even as starting points, for "serious" researchers. There is a subject-specific encyclopedia for almost any discipline or topic imaginable - some are e-books and some are available only in a print format. Most academic disciplines have one or more "authoritative" or "standard" reference works. The database Reference Universe indexes most of the library's specialized reference works regardless of format.
Browsing through the book stacks of a library collection is an excellent way to get ideas for topics.
It is also useful to know that librarians build all sorts of topical guides.
Exploring the library's A to Z database list (and understanding how to use its filters) is another excellent way to get ideas for topics.
Some of the library's databases are designed for finding topics by browsing.
While searching a typical library database, a keyword search can easily be converted into a genuine topical search by clicking on interesting subject tracings.
Most modern database interfaces don't do a particularly good job of making it easy to use the syndetic structure of controlled vocabularies. This is a shame because that structure makes it easy to get ideas and to understand the specificity of your topic. Students who know how to tap into the syndetic structure of Library of Congress Subject Headings (LCSH) will never be at a loss for generating ideas for research topics or adjusting them to the right level of specificity.