To begin to search successfully you must use a variety of words that relate to your topic
Think of the different words and phrases that people use when they discuss your topic.
Consider broader and narrower words, and synonyms (words that have the same meaning).
Identify search words through your background research or ask a librarian for help in finding words that are used in your field of research.
The starting research question "How do cigarettes impact children's health?" can be broken down into three key concepts: children AND cigarettes AND health.
I can brainstorm related ideas and synonyms to also search - and I will add to my list as I learn.
If you can't figure out what keyword will find you articles on your topic, select Subject Terms (in Academic Search Complete) or the Thesaurus (in ProQuest and browse for the Subject Term used by the database.
The Subject Terms list can also help you identify key subtopics, as in the second example below.
(click on image to enlarge)
When you search in the library catalog, databases, or the internet:
Use AND to narrow and focus your search.
Use OR to search for synonyms or like words.
Ex: "fast food" AND nutrition OR health
Use NOT to omit some results from a search.
Ex: NOT reviews
Use truncation symbols (usually ? or *) in library catalog, databases, and online to capture all forms of words
Keep searches simple using basic search words and phrases rather than natural language and sentences.
Use a variety of search terms and look for the terminology of the field and key concepts as you go. Keep track of the new words you find!
Try google advanced search (you can google for it!) to find search tips and tools.