Good researchers typically want to review a broad range of the existing scholarship on their topics. The process of examining relevant, previously-published materials is often referred to as conducting a "Review of the Literature" and many scholarly articles even feature a section called "Literature Review."
When you've found one article directly relevant to your research, the library's search engine makes it easier to find more like it. When you click on the title of an article that appears in your search results, you'll typically see a list of data about that article including publication information, an abstract, and often, a list of keywords, subjects, subject terms, or "descriptors" that can be used to begin a new, more focused search.
The terms used may vary, but most scholarly journal articles you find through the library's search engine will include a list of terms like those depicted above.