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Advanced Literature Search Guide for Health: STEP 5: Apply search techniques

Step 5: Apply search techniques

This page will explain a range of advanced search techniques, which you can apply to your search and improve your results. 

Search techniques

The following techniques are useful in improving your search strategy and can make a significant difference to your search results.

The way these techniques work can vary depending on which database you are using. Remember to always check the database help pages before you start searching

Search terms

The key to successful searching is choosing the right search terms. Rubbish in = rubbish out so it is worth taking time to get these right.

Make sure you take the time to select and develop your search terms. See Step 3 for more information on this. 

Boolean operators

The three Boolean operators (AND, OR and NOT) allow you to combine search terms in different combinations.


AND narrows your search. It is usually used to combine different concepts to make results more relevant.

When you combine search terms with AND your results will have to contain all of the search terms. 

AND is used for combining different concepts e.g. diet AND cancer


OR broadens and is usually used to combine synonyms or “like” words to make results more comprehensive.

It is used for finding similar words e.g. diet OR nutrition 


NOT narrows by reducing the number of results you retrieve by excluding a search term.

For example: nursing NOT children.

TIP: use AND NOT when searching in Science Direct.

Truncation and wildcards

Truncation and wildcards are useful for finding singular and plural forms of words and variant endings.


Shorten your keyword to its "stem" or "trunk" and add the truncation symbol, usually an asterisk (*). 

For example: 

Nurs* finds nurse, nurses, nursing

Child* finds child, children, childhood, childbirth etc.

Be careful not to truncate your words too early. For example, a search for count* would find country as well as count, counts, counting etc. 


Wildcards work in a similar way, but within a word. 

The symbols can vary, but are usually *, # or ?. Check the help or search tips section of the database for more information.

You can use them, for example, to search for variant spellings: 

Colo?r find colour or color

Phrase and proximity searching

Phrase and proximity, or adjacency, searching can be used for searching for phrases and words in close proximity.

Phrase searching

Using quotation marks searches for the phrase as a fixed string which may limit the number of results you find.

This is useful for where you have a phrase of more than one word in your search. 

For example: 

Pain management: will search for these two words separately, so they may both appear, but not in relation to each other. Some results may not be relevant. 

"Pain management": will search for this phrase exactly.

Proximity searching 

Searches for words near to each other, but not necessarily next to each other or in a particular order. This can vary quite a bit between databases, so always check the help or search tips section in the database for more information.

For example: 

Pain N2 management: Finds pain within two words of management. As word order is disregarded, this might also find management of severe pain. 


Searching with subject headings

Subject headings are a controlled vocabulary that a database uses to classify what an article is about. They are sometimes referred to as controlled terms or thesaurus terms. Using subject headings can improve your search results and should be used in systematic searching when possible. 

Extra resources

Below are some extra resources for you to take a look at to learn more about the search techniques explained on this page. 

Database search examples

Below are links to videos showing example searches in different databases. 

All images included in this guide are available from Upsplash through Creative Commons licensing CC-BY-2.0