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:
Ulrich's will usually have most of this information listed in some way.
For more information on using and searching databases, visit the LibGuide linked below.