Keywords and search syntax


Keywords represent the main concepts of your research topic. Use these when searching databases and search engines to find the information you need.

For example, a research question might be:

What are the effects of social media usage on mental health among adolescents?

The concepts for this topic are:

  • social media usage
  • mental health
  • adolescents.

Expand your search concepts


Different authors use a wide range of terminology and spelling variants to describe the same concept. Identify synonyms, including alternative words and phrases, to expand your search and capture a broader range of relevant results. 

Use a concept table to keep track of your results.

The example below is based on the research question: 

What are the effects of social media usage on mental health among adolescents?

Concept 1: Social Media Concept 2: Mental Health Concept 3: Adolescents

Online social networking

Social media platforms

Digital communication

Social media engagement

Psychological wellbeing

Mental disorders

Psychological distress

Emotional wellness

Psychological impact



Young adults



Acronyms are commonly used in various fields and industries to represent long and complex terms. 

By including acronyms in your search strategy with a Boolean operator (OR), you can retrieve comprehensive results that include the acronym and its expanded form. This helps you avoid missing relevant information that may not use the full term.

Search example: “National Aeronautics and Space Administration” OR NASA


Many words have different spellings but the same meaning. This is often the case with American/British variants. 

To capture multiple spellings of the same word, use a search technique called a wildcard. The wildcard symbol is often represented by a question mark (?).

To check the wildcard symbol in a database, see the Help section in the database.

Search example: colo?r will retrieve results for “color” and “colour”.


Find alternative word endings by placing a truncation symbol next to a word. The truncation symbol is usually an asterisk (*).

To check the truncation symbol in a database, see the Help section.

Example: Educat* will retrieve results for “educate”, “education” and “educating”.

Boolean operators

Boolean operators (AND, OR and NOT) are placed between keywords to build a search strategy. 


The AND operator specifies that all the applicable keywords must be included in the results list. Use AND to narrow your search.

Example: Hospital AND infection.


The OR operator specifies that at least one of the keywords that have been used is present in a result. Use OR between synonyms to broaden your search.

Example: “Young people OR Teenagers OR Adolescents. 


The NOT operator will narrow your search results by excluding specific words to filter out irrelevant information. 

Example: Exercise NOT Diet.

Search syntax 

Exact phrasing

Phrase searching is used to find results that include a set of words in a specific order. Retrieve results for an exact phrase by enclosing your phrase in “quotation marks”.

Example: “Climate change” will only retrieve results that contain the exact phrase.


Use proximity searching to find results that contain specific terms within a certain distance of each other.

Proximity operators vary between databases. Examples include NEAR, WITHIN or ADJ.  
Check the Help section of a database to confirm the syntax for proximity searching within that database. Some databases also allow syntax for proximity searching where words must occur in a specified order.

Example 1: Pet N3 dog will retrieve all the results for the terms “pet” and “dog” if they appear within 3 words of each other in the title, abstract or article. 

Example 2: Hospital W3 infection will retrieve all the results for the terms “hospital” and “infection” within 3 words of each other, but only if “hospital” comes before “infection”.


Nesting is the technique of combining search terms and multiple operators (like truncation, wildcards and Boolean operators) with parentheses to establish the order of operations. This creates more complex and precise search queries. 

Nesting allows you to control how search terms are combined and evaluated by the search engine or database.

Example: Obesity AND (P?ediatric OR child*) will retrieve results including obesity and either of the terms in parentheses. 

If you were to search for obesity AND p?ediatric OR child* without adding parentheses, the results will show anything that deals with obesity and p?ediatric together and child* alone.