Research is an ongoing process. Current research builds on work that has been done before.
Scholars are very careful to give credit to the sources they have used by citing them. You can use one article to find others on the same topic by seeing what sources the author used, and who else has used this author's article since it was published. This process is called citation mapping.
One article will often have dozens of citations in its References list. If you find a good article, look in it its References to find others on your topic. Many databases make this easy by providing a link to all of the cited sources. The link may be labeled "Cited References".
Another scholar may come along and use the same good article that you found as one of its sources. Of course, the scholar will list this in their new article's References list so the original article has now been cited by a newer article. If you find a good article, see what other articles have subsequently cited it. Some of these may also be related to your topic and they will also be more recent. Many databases have a feature that links from one article to others that have cited it. This link may be labeled "Times Cited in this Database" or "Citing References" or "Cited By".
Adapted from: Education University of Hong Kong (2016). Research Tool for Excellence. Retrieved from http://slideplayer.com/slide/4930139/16/images/24/Citation+Map+Cited+by+Cited+by.jpg
Many research databases will link to other sources which have cited a specific article. Here is an example from the PsycINFO database:
In this case, 384 other sources in Google Scholar have cited this 2003 journal article by Terrill and Reisig.
When you click on the "Cited by 384" link, you will see a list of those 384 citing references. The results include books, and many other types of sources, not just journal articles.
Google Scholar does not usually provide the full-text for articles for free, so you might get prompted to pay for access to an article.
Do not pay for articles! It's quite likely that the KPU Library subscribes to the journal. If we don't, we can get it for you free of charge.