Look at the bibliographies, footnotes and reference lists in the articles you have already found!
These will lead you to other relevant sources, both secondary and primary sources.
A good general database that covers all academic topics is Academic Search Complete. The database primarily covers academic journals, but you may find citations to general magazine publications in your results. To limit your search to just scholarly peer reviewed articles, check the box in the "Limit To" section on the left menu:
You may need specialized databases, depending on the nature of your topic. Here are some specialized, subject-specific databases:
If you need help selecting a database or the subject of your paper isn't listed here, please contact Laurie Sauer (309-341-7788) for further assistance.
Good database search strategy includes knowing enough about your subject to begin a search. Before searching for journal articles in a database, try to read about your topic in your textbooks or in some general books or reference books (click on the Reference Sources tab above to find some good ones). A basic familiarity with your topic will help you when selecting keywords for database searching.
Keyword Selection
It is always a good idea to broaden your search using synonyms. For instance, when searching for articles about African Americans, the following keywords work as synonyms:
african americans
african-americans
blacks
Depending on your topic, other concepts may have appropriate synonyms. Brainstorm the possibilities.
Look at your topic for facets that may describe it and either broaden it or narrow it with appropriate term. For instance, if you were researching the artistic culture of the Harlem Renaissance, you would include the terms
art OR music OR jazz OR culture OR literature
in your search in addition to the term "Harlem Renaissance."