Scholarly Journals vs. Popular Magazines
Scholarly journals are concerned with academic study and contain research. They often use a process of peer review prior to publishing an article, whereby other scholars in the author's field or specialty critically assess a draft of the article. These journals are "peer-reviewed" or "refereed." Articles in scholarly or peer-reviewed journals cite their sources in footnotes or bibliographies.
To determine whether or not a journal is peer-reviewed, you can look it up in Ulrich's Periodicals Directory (shelved at the Reference Desk).
In many Online Periodicals Indexes, you can search for articles in peer-reviewed journals only.
Popular magazines are written for the general public and reflect their tastes and intelligence-level. Magazines can contain substantive news, articles concerning current events, or other topics of general interest.