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CHEM 151 (Roberts): Search terms

Search for books and articles using keywords

1. Your First Keywords

The first keywords you try in your searches will probably come from:

  • The research topic your teacher gave you
  • Vocabulary used in your textbook and in class discussions
  • Your natural way of describing your topic

2. Check a thesaurus: Better keywords = better articles

You'll probably need to find better keywords as you learn more about your topic.  You can collect additional keywords from:

3. Run a test search! Perfect your search strategy by 'mining' the best articles for the most powerful search terms:

Using the thesaurus terms and your own keywords, test your search strategy. Pick the best 1 or 2 articles in your search results, and refine your search by 'mining' for search terms within them:

Database controlled subject terms




  • natural language words describing your topic - good to start with
  • pre-defined "controlled vocabulary" words used to describe the content of each item (book, journal article) in a database
  • more flexible to search by - can combine together in many ways
  • less flexible to search by - need to know the exact controlled vocabulary term
  • database looks for keywords anywhere in the record - not necessarily connected together
  • database looks for subjects only in the subject heading or descriptor field, where the most relevant words appear
  • may yield too many or too few results
  • if too many results - also uses subheadings to focus on one aspect of the broader subject
  • may yield many irrelevant results
  • results usually very relevant to the topic


Putting keywords together: building a search strategy

Putting Keywords Together

AND goes between keywords that you want to add together from different columns

“ “ [double quotes] go around key-phrases (i.e., when your key term is made up of more than one word, eg. "yellow fever")

OR goes between keywords that are from the same column—use ( ) to group them : best for synonyms or closely related terms, eg. (fear* or anxiety) AND (shy* or timidity)

N3 goes between words that you want to find close together in the articles

* [asterisk] goes at the end of a word stem that could end in multiple ways (eg. play* searches for play, plays, played, playing, player, players)



 stress AND children

 Use AND to narrow your search to get fewer but more focused results.

 elderly OR geriatric

 Use OR to broaden your search to get more results.

 post traumatic stress disorder

 Use double quotation marks to search for a phrase

 stress AND prevent*

 Adding an asterisk (*) will search for prevent, prevents, preventing, prevention, etc.

 stress AND (exercise or  fitness 

 Searches for either exercise or fitness and combines them with stress.

Boolean operators

courtesy of PGCC Library

How many search terms?