While you should evaluate each source you use, the journals found in the library's databases have been checked to ensure they present high-quality sources of information.
First make sure you are looking at a journal and not a magazine, trade publication, or other type of periodical. If unsure, here's more information on understanding different types of resources.
Things to look for:
- Functioning Website
- Peer-Review
- Scope of the Journal
- Editor(s) Information
- Any Institutional Affiliations?
- Membership Fees and/or Advertising Policy?
- If Open-Access, are they listed in the DOAJ?
Ulrich's will usually have most of this information listed in some way.