• when doing scholarly research
• to find out what has been studied on your topic
• to locate original research articles

to find bibliographies that point to other relevant research

Journal articles are written by scholars in an academic or professional field. An editorial board reviews articles to decide whether they should be published. Journal articles may cover very specific topics or narrow fields of research. Some journals are Peer-Reviewed or Refereed - a process in which an author's scholarly work or ideas is reviewed and evaluated by experts in the field prior to publication. 
 
Since journals are published at periodic intervals, they are grouped in the category called "periodicals." They may be in print format or on the Web as electronic journals. Your library purchases subscriptions to many journals and provides free Interlibrary Loan to access those not owned.
 
Examples of Journals

• Journal of Communication
• The Historian
• Journal of Business
• Lancet