When doing research, use literature that is peer reviewed. You might also see it referred to as scholarly or refereed.
Articles are reviewed by subject experts prior to publication.
The most thorough way to find if an article is peer reviewed is to visit the journal publisher's website, locate the journal title, and read the section About this Journal (or similar) which will indicate if submissions to that journal go through a peer review process.
PubMed is comprised of scholarly literature. Other Logan databases have options, usually in the advanced search, to limit your results to peer reviewed information. See tutorials for individual databases to learn how to locate peer review material in each Logan database.