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CINAHL Guided Exercise: 3. Keyword Search

3.  Add a Keyword Search

What is a Keyword?

Keywords are specific words chosen to represent a concept. Searching for them in the title and abstract fields will locate papers where the concept is highly relevant.  Keywords are also called textwords or natural language. 

In this module, you will learn how to find relevant keywords, or natural language for our first, or P, element.

Remember, for each PICO element we will perform both a Subject Heading and a Keyword search.  Each type of search has different advantages that will make our search more relevant.

Keywords are helpful when:

  • An appropriate subject heading does not exist
  • The term is very specific, jargon or a brand name etc.
  • The concept is new to the literature
  • The search term is a condition or therapy that is very rare
  • The paper has not been indexed as it is either too recent, or not indexed in CINAHL

Be aware: In most databases the search engine is looking for a match of the keyword in the Title and Abstract, not the full text.

When using keywords or natural language we need to take into account:

  • Spelling variations
  • Synonyms
  • Plural forms 

Many of these can be addressed by using Wildcards.  See: Using Wildcards below.

Now let's do the keyword search. 

Consider again the research question: "In infants, does using disposable diapers vs. cloth diapers affect the likelihood of diaper rash?"

In Step 2, we identified the subject heading Infant.

For each concept search we will perform a related keyword search in addition to the Subject Heading Search.

From the Used For list in the Scope Note for infant we noticed that a related keyword for our subject headings is: infants, in its plural form.

Step by Step: Adding a Keyword Search

Keyword Search

  1. Above the search bar, leave the checkbox “Suggest Subject Terms” unchecked.
    • Type our first keyword: infant*
      • The asterisk * is a method of truncation - see Using Wildcards
    • Type the operator word: OR
      • See Using Operators for more information on operators
    • Type additional keywords: newborn*
      • CINAHL's search will suggest some potential combinations of synonyms. These are useful for inspiration, but should not be selected in place of typing out our keywords as they will not make use of wildcard operators.
    • Your search query should now look like: infant* OR newborn*
    • Type additional keywords: baby OR babies
      • We cannot use truncation in this case because the stem word "bab*" would capture a variety of unrelated words that start with 'bab-' (babble, a disease named Babesiosis, etc.).
    • Your search query should now look like: infant* OR newborn* OR baby OR babies
    • Type additional keywords suggested by the dropdown: OR neonate
    • Your search query should now look like: infant* OR newborn* OR baby OR babies OR neonate*
    • Click Search
  2. Your search is displayed under your previous search in your Search History (Figure 1 : Search History) without "MH" in front of it. This indicates that it is a keyword search.
Video Demo: Keyword Search


Operators are syntax to combine search terms
Venn Diagram: Boolean Operator OR
Boolean Operator OR

Venn Diagram: Boolean Operator AND
Boolean Operator AND
  1. OR : Retrieves any or all search terms; therefore retrieves mORe results
  2. AND : only returns results that contain ALL search terms; therefore returns few results

Wildcards / Truncation

Wildcards are useful for finding variations of the search term.

  • Truncation is useful to find variations in the ending of search terms
    • Asterisk (*) wildcard at the end of a stem will capture variations to the end of the term of any length
    • injur* will return both injury, injuries
  • Wildcards can be used to find variations in British vs North American spelling. For example:
    • Wildcards # and ? find variations of spelling within the search term
    • Wom#n finds woman or women; colo?r finds colour or color
  • For more details see the Truncation and Wildcard Symbols Guide

Quotation Marks/Phrase Searching

If you need to search a phrase made of two or more words, use quotation marks to mark the combination as a phrase.

  • Searching for diaper rash without quotes will retrieve all results with the words diaper and rash, even if the two words do not appear together.
  • Searching for "diaper rash" with quotes will retrieve only results where the words diaper and rash appear together in this order.
  • For more details see the Truncation and Wildcard Symbols Guide

Title & Abstract Search

CINAHL's default search includes the fields of Title, Abstract, Subject headings, PubMed ID (PMID), Digital Object Identifier (DOI), and Author. Of these, both Subject Heading and Author would bring in unwanted results. Our search would include:

  • All subject headings which we did not select but which include the word "infant"
  • Papers regardless of subject by authors with names (especially last names) like Infante, Baby, and Newborn (totaling over 1,000 papers at time of writing)

To use a Title & Abstract search, add these additional steps before clicking "search":

  • Title Search:
    • Create your keyword search string as above in the first search box.
    • Select TI (Title) from the dropdown menu labelled "Select a Field (optional)" beside the first search box.
  • Abstract Search:
    • Change the "AND" operator before the second box to "OR". Do not skip this step. It can be easy to forget.
    • Copy your set of keywords from the first box. Paste them into the second box..
    • Select AB (Abstract) from the dropdown menu labelled "Select a Field (optional)" beside the second searchbox.
  • Click "Search"

Your search string will now look like: TI ( infant* OR baby OR babies OR newborn* OR neonate* ) OR AB ( infant* OR newborn* OR baby OR babies OR neonate* )

Searching within the title and abstract fields only, rather than in the whole record about the article, is more precise and will focus your search.

Video Demo: Title and Abstract Search

Continue building your search

  1. Using steps 1-2 for the keyword search, find suitable keywords for your P, or first, concept.
  2. Type your keyword in the search box.
  3. Click Search to add it to your search history.


  • Think of all types of words that match your concept
  • Are there any synonyms?
  • Are there variant spellings and endings? Can I use truncation?
  • Is there a suitable wildcard to incorporate any variations?