Articles are part of Journals.
Journals are found either by title or through Databases.
Databases are found by title or subject.
Library Subject Guides are a good place to start looking for information. Each of the over 80 guides lists resources that are the best for a given subject.
Databases A-Z list is good if you know the name of the database you want to use.
eJournals A-Z list is good if you want to jump directly into a journal you want to use. Especially good if you have a citation and are trying to find a specific, known article.