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NURB 361: Introduction to Nursing Research

For Suzi White's students

Boolean Operators

Boolean operators are based on math and logic. 

They connect your search terms to either narrow or broaden your results. 

The three main Boolean operators are AND, OR, NOT. 


AND = reduces the number of results

 ex:  cats AND felines          will only pull records that have both "cats" and "felines" mentioned in them.

  • AND is implied in many databases if you list your search terms


OR = increases the number of results.

ex:  cats OR felines            will pull records that have either the word "cats" or the word "felines," which will increase the number of possibilities.


NOT = reduces the number of results 

ex:  cats NOT felines          will pull records only mentioning "cats" and will exclude any record mentioning "felines."  

  • Databases usually give "AND" precedence and will join those terms first.
  • Enclose the words you want joined with "OR" in parentheses. 
  • ex:  dogs AND (cats OR felines)

Video Tutorial

Filtering the database

Limiting the Number of Databases

  • Camden-Carroll Library has 171 databases.  You can find the most relevant databases for your search by narrowing down your options.
    • On the Databases A-Z list, click on "All Subjects."  Scroll down to find your topic, in this case, it would be "Nursing."  
    • Click on "Nursing" and you will see there are 22 relevant databases.
    • If you would like to further reduce your number of options, click on "All database types," and you will see various options.
    • For instance, if you want to limit results to "Journal Literature," you will notice there are 14 relevant databases.
    • So, there are 14 available databases that match "Nursing" and "Journal Literature."

Filtering Within the Database

  • Once you have chosen a database, you can filter within that database to make your search easier.  
  • You can do an "Advanced Search" option and "Select a Field" within the database.
  • And/or you can scroll down the page and apply various limiters like "peer reviewed," "first author is a nurse" (in CINAHL), "full text," and so on.  

Keyword vs. Subject-Headings

Keyword Searching

  • The type of searching with which most people are familiar
  • Use words or phrases that describe your topic
  • Enclose phrases in quotation marks to make sure the database searches that exact phrase, instead of the individual words of the phrase.
    • ex:  To search for the Animal Welfare Act, which was signed into law in 1966, you would need to search "Animal Welfare Act" in quotations.  Otherwise, the database will pull results where the individual words are in various places in the record, meaning the results may actually have nothing to do with the law you are seeking. 
  • Use Boolean operators if necessary to combine words and phrases, or use the Advanced Search options.

Subject Headings/Controlled Vocabulary

  • Subject headings are used to help you find related information more efficiently.  They are the way a database or catalog defines a topic, which means you can find more relevant results quicker than with keyword searching.
  • To find subject headings for your topic:
    • Look to see if the database has an online thesaurus for subjects that match your topic.  You will probably need to check the Help Screen in the database.
    • Start with a keyword search, using those words or phrases that describe your topic.
    • Browse the results and choose a few that are relevant.
    • You can also look at the Subject or Descriptor Field and note the terms that are used after doing a keyword search.
    • Redo your search, using those terms. 

Truncation and Wildcards


Truncation and wildcard symbols can vary by database.

  1. Check the help screens to see which symbols are used in a specific database.
  2. Common symbols are   * or !
  3. Use truncation or a wildcard symbol when:
  • Root words have multiple endings.  Example: sun = suns, sunshine, sunny, sunlight
    • Search for = sun*
  • Words are spelled differently, but mean the same thing.  Example:  color, colour
    • Search for = colo*r