Journal articles provide in depth scholarly information. They are vetted and improved by peer review. They are usually fairly short in length and focused on discussing one specific issue. The following indexes are good places to find journal articles about political science.
When you find a title of interest, if the full text is not immediately available (as in JSTOR and Proquest), use the Find It button to go to the full text directly or get a request form to have a digital copy of the article sent to your email address in around three days.
See the Search Tips tab for examples of ways to develop terminology and construct search statements.
These two databases are especially useful when looking for very current information. They are also helpful in providing cross-disciplinary approaches to issues.
Usually researchers find more sources by looking at the footnotes in an article or book, but these will always be older than the publication you have in hand.
Citation indexes like the Web of Science (which includes sections for the Social Sciences, Arts and Humanities, and Science) are set up to search for sources cited in the footnotes of journal articles as soon as they become available.
This allows you to find newer articles which cite the books and articles you already know are key for your topic. By relying on connections between authors rather than subject words and by moving forward in time, citation searching can open up new avenues of research.