Articles contain the most current information published in a field of study. The Library Catalog contains the journal titles to all of the print and electronic format journals to which we subscribe. The Catalog does not list the articles within the journals. Articles are in article databases.
Most professors and researchers prefer articles that are "scholarly" or "peer-reviewed" in nature. The table located here: Popular vs. Scholarly Periodicals describe characteristics of scholarly journals to help you make the distinction
If you are still uncertain about the scholarly nature of a journal, you all look up the title or ISSN in the periodical database Ulrichs Periodical Directory (UlrichsWeb). This database will tell you about the journal including the nature, it's audience, and in which databases it is indexed and abstracted.