Did you find something interesting listed in an article's bibliography? Locate that older article by using the Journals search tab. Look up the title of the journal where the article was published, then look for volume and/or date it was published.
If you have an article on your topic and want to find newer, related articles, try using Google Scholar. Search on the title of the article, then click on "cited by" under the matching result.
Note: Not all articles are in Google Scholar, and not all have been cited.