What's the difference in the "journal article title" and "journal title"?
A "journal article title" is what each article, within a journal, has been titled by its author.
Journals are similar to magazines, except that they contain academic, scholarly content that generally has been reviewed by experts in the content field around which the journal focuses, i.e. "peer-reviewed journal." A journal title is what the journal itself is called.
So, for example, our library gets the journal, Social Work & Christianity (this is the title of the journal). Within the Spring 2012 issue of this journal, I'm looking at an article titled "Is that Church on Fire? A Unique Moment of Opportunity for Social Work Leadership" written by Diana R. Garland.