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Searching with keywords

It is best practice to search using both subject headings and keywords. To develop your keyword search, you need to follow the three steps below:

Three connecting boxes showing the process of searching with keywords. First identify alternative keywords for each concept, then combine alternative keywords and concepts with connectors, and finally simplify your search with truncation, wildcards and phrase searching.

Identify relevant keywords

Academic authors can use a variety of terms when describing the same idea, so it is important that you include all relevant words in your search strategy - databases will only yield results that match what you enter!


  • Terminology - physiotherapy/physical therapy
  • Spelling - labour/labor
  • Singular and plural words - child/children
  • Generic/specific - acetylsalicylic acid/aspirin
  • Acronyms - cognitive behavior therapy/CBT
  • Words with/without hyphens - nonsurgical/non-surgical
  • MeSH - the heading word and entry terms should be included in your keyword line
  • Reference texts - entries tend to start with a list of alternative terms

In your PCC breakdown, you would have identified the relevant alternative keywords. 

For example:

PCC Term Keywords MeSH






   Chronic disease

   chronic disease

   chronic illness


   noninfectious disease

   Chronic disease/

   Nurse-led care models

   nurse-led,  nursing led
   nurse run, nursing run
   nurse managed, 
   nurse practice patterns

   Practice patterns, 


   High income countries

   first world countries,
   developed nations,
   industrialised nation/s

   Developed countries/


Each separate element will become a keyword line in your search strategy.

Combine keywords with connectors

Next, you need to combine your keywords with the connectors AND and OR.

Circle icon with connector OR

connects alternative keywords within a concept to broaden your search.

Circle icon with connector AND

connects different concepts to narrow your search.

Circle icon with connector NOT

removes terms. Avoid using NOT as it can remove relevant results.

The video (3:11) below provides more information:

For our example:

  • Combine all the alternative terms in each line with the connector OR
Chronic disease OR chronically diseased OR chronically ill OR chronic illness OR non-communicable disease OR noncommunicable disease OR non-infectious disease OR noninfectious disease


  • Then combine each each line with the connector AND:
Chronic disease OR chronically diseased OR chronically ill OR chronic illness OR non-communicable disease OR noncommunicable disease OR non-infectious disease OR noninfectious disease
Nurse-led OR nursing led OR nurse run OR nursing run OR nurse managed OR nurse practice patterns
1st world countries OR developed nations OR industrialised nations

Simplify keywords with truncation, wildcards and phrase searching

Truncation - Most databases allow you to find word variations by using a feature called truncation. Use a symbol, often the asterisk * (select shift 8 on your keyboard), to substitute for characters after a word stem.

It is highly recommended you use truncation to include all variations of a word in your search.

e.g. nurs* finds nurse, nurses, nursed, nursing

Limited truncation - allows you to specify how many letters you want to find after a root word. This is only available in some databases, for example MEDLINE, Embase and PsycINFO.

e.g. nurse$1 finds nurse or nurses or nursed, but NOT nursing

Wildcards - allow you to find different word spellings. The symbol will find one character, or no character only. The wildcard symbol can vary between different databases, so always check the help screens.

e.g. p?ediatric finds pediatric or paediatric
       organi?ation finds organisation or organization

Phrase searching searches for an exact match for your keywords.  Most databases require you put phrases in double quotes to search for phrases.

e.g. "nurse-led models"

The one exception is Ovid databases (for example: MEDLINE, Embase, PsycINFO). Ovid only requires double quotes when your phrase contains a preposition.

e.g. "practice patterns of nurses"


Note: Cut/copy and paste from Word documents can cause issues due to code. You may find it best to use a plain text editor. In some cases (e.g. double quotation marks) you  may need to manually type in elements of your search.

For our example:​

"chronic* disease*" OR "chronicill*" OR "non?communicable disease*" OR "non?infectious disease*"
nurse-led OR "nursing led" OR "nurs* run" OR "nurse managed" OR "nurse practice pattern*"
"1st world countr*" OR "first world countr*" OR "developed nation*" OR "industriali?ed nation*"

Limit your keywords to specific fields

Database records contain descriptive information about publications organised into searchable sections called 'fields'. Targeting your search to specific fields can be a powerful tool when designing your search strategy.

By default, most databases will search for the terms you enter in a variety of fields. For example, in Ovid MEDLINE you will see

mp. [mp=title, abstract, original title, name of substance word, subject heading word, floating sub-heading word, keyword heading word, organism supplementary concept word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier, synonyms]

Here, mp stands for 'multi-purpose'.

You may be able to improve the relevancy of your results by searching for terms in specific fields.

Recent change (Sept 2021): Embase and Emcare now align with MEDLINE with .kf for author supplied keywords

Commonly used fields for systematic reviews: databases available via Ovid (selection)

Database Title Abstract Author supplied keyword Textword - combined fields
MEDLINE .ti .ab .kf .tw (includes Title and Abstract)
Embase .ti .ab .kf .tw (includes Title, Abstract, and Drug Trade Name)
Emcare .ti .ab .kf n/a
PsycInfo .ti .ab n/a .tw (includes Table of Contents, Title, Abstract and Key Concepts)

How to use field codes - example searches:
(chronic pain OR recur* pain).tw - use brackets when combining terms
(chronic pain OR recur* pain).ti,ab. - use a comma to combine fields

For a full breakdown of all available fields within any Ovid database click the 'i' icon to the left of the database name which will take you to the Field Guide for your selected database:

Image of 'i' icon within MEDLINE database

Mining for keywords

When developing a comprehensive list of keywords, the following tools may be useful to explore:

Key guides

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