
Boolean operators are ways of linking more than one keyword. They come 
  in three basic flavors: AND, OR, and NOT. When you use them, you can 
  limit or increase the number of titles you come up with, also known as 
  "hits." 
  AND  is a limiting operator. When you search for peanut AND butter, 
  you'll find only those titles or Web sites that mention both "peanut" 
  and "butter."  You won't come up with peanut sauce, nor with almond 
  butter, but you will find peanut butter and may find a recipe for peanut 
  cookies made with butter. 
  OR  is an expanding operator. If you search for peanut OR butter, you'll 
  find everything that mentions peanuts and everything that mentions 
  butter. If you're just looking for "peanut butter," this isn't a good 
  way to do it. If you're looking for information about a topic that 
  people refer to in more than one way, however, OR is a good choice. For 
  example, you would want Cambodia OR Kampuchea if you were looking for 
  information about that country. 
  NOT  is a limiting operator. Searching for peanut NOT butter would 
  eliminate references to peanut butter and to the peanut cookie recipe 
  that uses butter. If you just wanted information about growing peanuts, 
  it would be a good approach. 
  You can put more than one Boolean operator into the same search, though 
  it's not wise to use too many at once. 
  
  Practice:
  
1. List topics you might get with the following:
  
a) rainforest AND trees
  
b) rainforest NOT trees
  
c) rainforest OR trees
  
  
2. How would you search for information about rainforests that are 
  outside the US? 
  
3. What would you put to get information about family planning in China?
  

4. Which letters on 
  the diagram above show A and B and C? 
Which show A or B?
  
Which letters are (A or B) not C?
  
Which show B and C?
  
Which show (B or C) not A?
  
  1. Put the following terms in order from broadest to narrowest:
  
Central America
  
Costa Rica
  
Latin America
  
San Jose, Costa Rica
  
  
agriculture
  
ecology
  
forest
  
Oregon rainforest
  
rainforest
  
temperate rainforest
  
  
2. You're interested in the rainforest in Costa Rica, but you're not 
  finding much. What synonyms could you use to make a broader search? 
  
3. You want to find out about endangered species, but there's too 
  much information. How will you narrow your search? 
    If you have questions, comments, or for more information, 
    contact Deborah Healey, dhealey AT uoregon DOT edu
  
  https://www.deborahhealey.com/techtips/feb1996.html
    Last 
    updated 26 June, 2009