When you are searching in a database, remember that these resources think differently from you. You need to use special terms to get the database to give you good information.
If you want to connect two concepts, use the word AND. That will give you a list of articles that contain both the concepts you connect.
If you want to look for multiple independent concepts, use the word OR. That will take each word you connect and give you a list of articles that contains either or both concepts.
Some databases also use NOT to exclude information. If you use NOT, the list of articles should remove all articles with the word after NOT.