There are a number of techniques and strategies you can use to make your search more effective. The sections below detail some of these techniques.

Using Subject Headings

Some databases have a thesaurus which you can use to generate keywords. These can also be known as lists of controlled vocabulary.

An example is CINAHL FT, where this function is known as CINAHL Headings.
If you enter postnatal depression in the search box, the database will suggest you use depression, postpartum as your keywords.

CINAHL with Full Text

Using the Advanced Search

Most databases have an Advanced Search function as well as the basic search. The example shown below is from ProQuest Central.



You can use the advanced search to narrow a search by selecting which database field to search, author, title, source etc.


ProQuest Advanced Search


Boolean Logic

Boolean operators allow you to manipulate your search results to make them more effective.

Using two operators

teenagers OR adolescents

We have used OR to make the search as comprehensive as possible. In some research pieces the writers may have used the term (keyword) teenagers and in others they may have used the term adolescents.
By using the OR we ensure the results include both (or either) terms.

To summarise: use OR if you want to widen your search or if your keywords have obvious synonyms

If you want to search for multiple keywords simultaneously use the AND operator. Most searches contain more than one topic or require a context for their subject. To search for information on teenage drinking the term alcohol has been added to the search conducted above.

 Adding another keyword

 teenagers OR adolescents AND alcohol

To summarise: use AND to add a second keyword or term.

If you need to exclude a topic from your results use NOT to exclude a term. You may, for example, want to consider aspects of teenage drinking that don't include binge drinking.

Excluding a topic

teenagers OR adolescents AND alcohol NOT "binge drinking"

To summarise: use NOT to exclude a term


Synonyms are alternative words or phrases which mean the same thing. You can use the Boolean operator OR to include synonyms in your searches.

For Example:

Free OR Liberated.

NHS OR National Health Service.


To make even better use of Boolean operators, you can use parentheses to nest query terms within other query terms.

For Example:

(essay OR report) AND “clothing manufacturers”

N.B. You can enclose search terms and their operators in parentheses to specify the order in which they are interpreted. Information within parentheses is read first, then information outside parentheses is read next.

Phrase Searching

Phrase searching is when you use quotation marks to find an exact phrase.

For Example: "health promotion"

The quotation marks ensure that the database will only return results with your phrase exactly as you have entered it, i.e. only results with “health promotion” rather than all results containing the words health or promotion will be found.


Truncation is when you use the * symbol to search for words which begin with the same letters

For Example: econ*

By using the * you will retrieve results such as economics, economy, economical etc.


Wildcards are used to search for alternative spellings. You can use the ? or * symbol to replace the required letter

For Example: organi?ation

You may find that some databases do this for you automatically. It’s worth checking the help button on the database you are using to check.