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Information literacy: Search techniques and search tips

Obtained from a University Library Groningen publication on

Too many results?

  • use more specific search terms. A thesaurus is the best place to look for these.
  • add an extra search term to your search query (AND)
  • search in specific search fields (title words, keywords)
  • use limiters (e.g. between specific years, or peer-reviewed articles only)
  • search for an exact phrase (use double quotation marks)

Make sure that while limiting your search you do not exclude an important aspect of your subject!

Too few or no results?

  • try to broaden your search terms (search with OR, or an overarching search term)
  • try to make your search less precise (e.g. search using “all words”)
  • use synonyms
  • translate the search terms
  • use truncation/wildcards
  • use suggested keywords

Keywords and subject headings



In catalogues and databases without controlled vocabulary use the search terms you found during the orientation on your topic as keywords.

Try all the variations and different combinations of search terms, using exact phrases, Boolean operators, truncations and wildcards.

Subject headings

Controlled vocabulary

Most databases use controlled vocabulary to describe the subject of a publication. To get the best search results you need to use subject headings from this vocabulary.

This means you need to match your keywords to the correct subject headings for the database you want to search. Most databases provide indexes or a thesaurus to help you find the correct subject headings.

For example:

Keyword CINAHL subject heading Medline Subject heading
Heart attack Myocardial Infarction Myocardial Infarction
Distance learning Education, Non-traditional Education, Distance
Electronic patient record Computerized Patient Record Electronic Health Records

You can also start by doing a basic search with your own keywords, select publications relevant to your research question from the search results and look at the subject headings added to those publications.

Select the appropriate subject headings and use these to start a new search.

Combine the subject headings using Boolean operators to fit your research question.

If you do this correctly you will find more relevant literature on your topic; even if the subject is not part of the title of a publication or if the publications is written in a different language.


A thesaurus is a list of subject-specific subject headings in a database (not every database has one!).

The thesaurus indicates which terms are broader or more general (BT= Broader terms), which terms are narrower or more specific (NT= Narrower terms) and which related terms (RT) can be used to search the database.

For example:

  • environmental pollution (= BT)
  • soil pollution (= NT)
  • environmental technology (= RT)


You can use the search operators AND, OR and NOT to combine search terms. These are the most commonly known and used operators.

The operators AND and NOT limit the number of results from a search. The operator OR does the opposite; it increases the number of results.


  • Endangered AND birds : combines these two words
  • Endangered OR birds : searches for the words endangered OR birds. This search will produce more results. (Tip: the operator “OR” can also be used to include different spellings and translations or synonyms in the search).
  • Endangered NOT birds : searches for the word ‘endangered’ and excludes the word ‘birds’.

To see how this works, take a look at The Boolean machine. Move your cursor over the operators AND, OR and NOT to see how they determine your search.

You can also combine more than two search terms. Use brackets to indicate the priority. For example (Money OR inflation) AND banking.

Wildcards and truncation

Truncation (or wildcard symbols) can be used to broaden your search and include different spellings.

To do this, you shorten the search term to a word stem and, depending on which database you are using, you type either a question mark or asterisk after the word stem. The results will then include various endings and spellings.

If you search with environ*, the results will include publications with ‘environment’, ‘environmental’ and ‘environmentally’ in the text and/or title.

A question mark replaces a letter in a word; the results include British as well as American spellings.

For example, if you search with organi?ation, the results will include the British English spelling (organisation) as well as the American English spelling (organization).

If you search with labo?r, the results will include ‘labour’ as well as ‘labor’.

Exact phrases

You can search for a specific expression or concept (e.g. “social media”).

To do this:

  • put the words in a single search box
  • put the words between double quotation marks
  • combine the words using AND

These actions will depend on the database you are using. Use the Help function for guidance.