Using Database Limiters
Another way to control your search is by using limiters. Usually listed in a drop down menu or as check boxes, they let you restrict your search by certain criteria. Some of the most useful ways to limit a search is by:
Search for "intelligence tests" for the years 2002-2004 for the most recent research, or for Iraq before 1991 for articles that predate the Persian Gulf War.
Article or Document Type
You may want to look for articles that are specifically: peer reviewed, or case studies,or book reviews, or interviews, etc. Each database will have its own list of types, so read them carefully. Also be aware that databases will include items beyond articles, like book chapters and government documents.
You can limit a search to just articles from a specific journal. Look for a field labeled Source, or Publication, or Journal Name where you can type in the name of a journal.
Some databases will give you the option to limit your search results only to articles that are full text in that database. This can actually hurt your research, causing you to miss important citations that can be found elsewhere in full text. When you first begin searching, it is better to leave the full text limiter unchecked.