Take a few minutes to review the following chart. This will help familiarize or reinforce the differences in types of articles you will find as you conduct your research. For your graduate research, you'll want to focus primarily on scholarly/peer-reviewed articles. Being able to recognize alternate forms of articles is an important aspect of the research process.
As you search in the databases, you'll see that some of them bring back results by article type, or they will give you the option to sort by article type. This can be a huge time-saver. If you can eliminate articles that won't be acceptable for your graduate level work, use the tools to do that.