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Pre-clinical Medicine: Searching

Guide to Oxford University library resources for Pre-clinical Medical Students.

Combining search terms

How you link your search terms together is important. There are 3 main ways:


If you link terms with AND, only records containing them all will be selected, e.g. cats AND dogs will only find records containing both. Adding further terms using AND makes your search narrower, as more terms must be present.

Some databases assume AND if you enter multiple terms. Sometimes you have to select it from a drop-down box. Sometimes "all my words" or similar is used.


If you link terms with OR, records containing any of the terms will be selected, e.g. cats OR dogs will find records containing either cats or dogs or both. Adding further terms using OR makes your search wider. You may need to select OR from a drop-down box. Sometimes "any of my words" or similar is used.


Using NOT in your search will exclude a term, e.g. child* NOT childish would find records containing child, children or childhood but exclude childish. NOT is another way of making your search more precise.


  • AND, OR and NOT are known as Boolean Operators.
  • Using the Advanced search option in a database will often guide you through constructing a search using these operators.

Proximity operators

Proximity operators allow you to specify that two terms must be within a certain distance of each other in the field being searched and/or in a particular order. They can be used for terms that are not picked up when searching for a phrase enclosed in quotation marks.


carers NEAR/5 support will find records where these two terms appear within 5 words of each other.

parent PRE/3 disabilities will find records where parent appears up to 3 words before disabilities.  


  • NEAR/n (n representing the number of words between 2 terms) can be entered as N/n, and PRE/n can be entered as P/n. 
  • Wn is a proximity operator used in databases on the Ebsco platform.
  • ADJ is a proximity operator used in databases on the Ovid platform.
  • Check the help page of the database to find which proximity operators are available, and how to apply them.





Plan your search

Ask a clear research question.

Break the question down into keywords.

Search for individual terms or phrases, rather than starting with a complicated search. You can then see which options work and which are worth combining.

Combine your searches using Boolean logic (see box on left).

Look for Advanced search or Multi-field search options - in some databases these give possibilties for manipulating results in your search history which are not available with the Basic search option.

Consider whether filters or limits should be applied to your search (see box on right).

Look at the subject headings or thesauri provided by the databases to help find relevant terms.


Choose your terms

Think about:

Synonyms. Are there alternative words or phrases for your search term? Searching for teenagers? Try also adolescents, young adults. Some databases include a thesaurus to help you to find preferred terms.

Alternative spellings. Could your term have more than one spelling, e.g. behaviour, behavior? Some databases search for alternative spellings, while in others you have to enter both or use a wildcard.

Wildcards. These enable you to search for terms with a common root. * is usually used for end truncation, representing any number of characters, e.g. child* will find child, children, childhood, etc., while ? is often used to represent a single letter, e.g. wom?n will find woman and women.

Phrases. Some databases assume multiple words are a phrase. In others you need to enclose your phrase in "quotation marks". There may be a drop-down box allowing you to specify your search terms as a phrase (e.g. "is exactly", "with the exact phrase").

Explode. Some databases have an option which will expand your term to show broader, narrower and related terms used in their thesaurus. You can then select some or all of them to use in your search.

Use your results

Related records ("Related citations", "Related documents","Find similar", depending on the database) can be a good way to retrieve information from other disciplines that keyword searching may miss.

"Find citing articles" and "Cited by" - following these options may lead you to other authors working in the field you are researching, or suggest new search terms.

If you find a record that is a really good match for your research question, follow this up by looking at the keywords, authors and publication. Any or all of these may then lead you to further relevant records.

If you find a journal that seems to fit well with your research, have a look at a few issues in hard copy - you may then get some ideas that wouldn't have occurred to you by seaching a database or e-journal.


Databases let you refine your search using a number of options, either when you first run the search or working with your search results. Typical ways to refine or limit a search are by:

  • publication date
  • author
  • subject
  • publication type
  • language

When viewing search results, limit options are often shown on the left side of the screen.


Different databases and search engines may have different search options available. To find out about them, look for:

  • Guidance and examples displayed on the screen
  • Links to Help screens
  • Online demonstrations or tutorials
  • "Mouseovers" - point the mouse at a screen option for a brief explanation

Please contact your Librarian if you would like more help in searching or using a specific database.