General criteria are available to help determine if periodicals and journals are scholarly, often called peer-reviewed journals, practitioner / professional journals, or popular magazines.
Consider such things as:
Authority - Who wrote the article? What qualifications or credentials do they have regarding subject?
Content - What style of writing is used? Is it objective or trying to sell you something? Is it fact or opinion?
Audience - Who is the intended reader? What reading level is the article (advanced, general)?
Citation - Is the article properly cited? Does it have a bibliography or footnotes?
Review Process - Has the article been reviewed by subject specialists?