Academic journals are scholarly periodicals (i.e. publications which come out on a regular schedule) which contain articles on specific subjects.
They are important in academic research for a number of reasons:
Use the Electronic Journals to check whether the full text of a journal is available electronically - this is useful if you are looking for a specific article. N.B. Search for the journal title rather than the article title.
Browzine is another way to search the library's journal collections--if you prefer getting information in a visual format, you may want to start here.