Research articles published in scholarly journals have in most cases been through a rigorous peer-review process. Other scholars have scrutinized the reasoning and methodology and decided that it meets their professional standards. This process provides a peer-reviewed article with a certain amount of authority.
When you refer to a scholarly, peer-reviewed article in your presentation, you are using that authority in the service of your own argument. This technique will help you be persuasive.
The library subscribes to a large number of databases with scholarly content. One approach is to use OneSearch and limit your results to Scholarly (Peer-Reviewed) Journals. If you are doing research in a particular area such as education, sociology, or psychology, choosing a database focused on that subject may help you screen out irrelevant articles that happen to contain the keywords you're using.