There are several ways to search for journal articles. You can start with UC Library Search, using the Articles, Books and more option, which searches all the databases the UCLA Library subscribes to. Or you can go to a specific database, such as APA PsycINFO, Academic Search Complete, PubMed, etc.
In either case, start with a keyword search using words relevant to your topic. When you see some articles that look interesting, click on the title to see the complete citation. If there are subject terms or descriptors, click on those that seem related to your topic to get other articles on the subject.