To find primary research articles, you will want to look in our article databases for "academic/peer reviewed articles." Many databases allow you to limit your search to "academic/peer reviewed articles" by clicking in a check-box on the search page.
You will most likely also want to select the full-text in order to only bring back articles for which the full text is available. Now search for your topic.
Remember that not all articles will use the same terminology, so think of various terms that could be used to describe your topic. You may need to search for several of these terms until you find the article you are looking for. You may find this LibGuide useful - it explains how to recognize primary research articles in the field of Biology.