When you want to find articles containing two or more ideas, you should connect the words in your search with AND. Using AND between keywords means that both terms must appear somewhere in the record. AND is used to narrow a search.

students AND Internet
Entering this search in a periodical index would find articles that contained the terms students and Internet. If an article only had one of these terms, it would not be retrieved by this search. AND is best used for linking different ideas.

students AND Internet AND assignments
You can use AND many times in a single search.