How to Write a Literature Review: Phrases

• Some databases assume that words typed next to each other should be searched as phrases.
• Others automatically put a Boolean AND between your search terms, requiring that all the words be present, but not necessarily adjacent to each other.
• These searches can retrieve very different results.

• Using parentheses or quotes around search words is a common way to do phrase searching, but not all databases or search engines use them.

Example: 

"genetic engineering" or (genetic engineering)

• Many databases allow you to specify that the words you are searching are within a certain proximity of each other.
• Because of their proximity the two words can have a relationship
• Proximity operators are more specific than Boolean operators and make your search more precise.
• Proximity operators also vary by database, but some common ones include: W# (With, Within) and N# (Near).

  • W# can specify that words appear in the order you type them

    • Substitute the # with a number of words that may appear in between. If no number is given, then it specifies an exact phrase.

  • Example: 
    cold W2 therapy, it retrieves: cold therapy, cold water therapy, etc.)

  •  N# can specify that the words may appear in any order.

    • Substitute the # with a number of words that may appear in between.

  • Example:
     cloning N3 human, it retrieves: cloning of humans, human cloning etc.)

• Proximity Operators vary from database to database (ADJ#, W/#, N/#, NEAR#, etc), you need to check the Help section of each database to see what they use, look for Proximity Operators or Proximity Searching

See original Search Map

Example: What is the risk of mortality due to cell phone use in distracted teen drivers?

Parentheses are extremely important in proximity searching.  Using parthentheses the search would look like this:

​(mortal* OR fatal* OR death) AND ((cell OR cellular OR smart OR mobile) ADJ1 (phone OR phones) OR smartphone* OR cellphone*) AND ((distract* OR inattent*) ADJ2 
(driver* OR driving))

 The asterisk at the end of some words is a wildcard which is used to find alternate endings, see Truncation for more information. 

See original search in PubMed without proximity operators. Note: the original search in PubMed retrieved 6 results where this search in OVID Medline with proximity operators retrieved 34. As a reminder PubMed and MEDLINE are essentially the same databases.

Searching Basics

1. Create a Searchable Question
2. Boolean Operators
3. Search Strategy
4. Subject Headings and Keywords
5. Phrases
6. Truncation
7. Fields
8. Limits

Consult a Health Sciences Librarian