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Databases allow you to do different kinds of searches.

Basic keyword search: similar to a library catalogue or Google search where you use whatever keywords you think describe your topic.

Subject heading search:  use the thesaurus terms (also known as controlled vocabulary) of the database to find all articles tagged with specifically assigned subject headings.

Combined keyword & subject heading search:  for advanced research, use combined searching  to ensure retrieval of current and relevant  resources to support your research.  Start with your own basic keywords as concepts but also find out what the thesaurus term in the database is for that concept and combine them. 

To search within MeSH:

  1. To browse a list of subject headings available in the database, click the MeSH button on the blue sub-toolbar.

        Users can search MeSH in MEDLINE in three different ways:

• Term Begins With  -  Enter a term in the Browse for field and choose Term Begins With. An alphabetical list is  displayed.
• Term Contains - Enter a term in the Browse for field and choose Term Contains. The term searched appears first, followed by terms that contain the term in alphabetical order.
• Relevancy Ranked - Enter a term in the Browse for field and choose Relevancy Ranked. The exact match for the term appears first in the list, followed by the relevancy ranked list.

   2. Mark the check box tho the left of a term.

   3. Click Search Database. Your search query finds articles with the term as a MeSH Heading.

Specific or Sensitive Search. Which one do i need?

The number, type & combination of terms you use in your search will depend on both your question & the objective of your research. A search cannot be both specific & sensitive. Your job as a researcher is to find the balance.

A specific search (also called precise or narrow search)

• requires a specific answer, is most likely clear & easily described with keywords &/or thesaurus terms.
  • e.g. What is the recommended daily dose of paracetamol for a child with fever?
•  may be one where you only need a few articles on a specific topic
  • e.g. use of flipped classroom techniques in medical education to stimulate student participation in lectures or you want a recent RCT on the effectiveness of diclofenac for osteoarthritis

 A sensitive search (also called a broad search)

• requires researcher to gather all relevant literature & includes the most recent evidence which may not yet have thesaurus term assigned;  
  • e.g. find all studies on the influence of diet on Rheumatoid arthritis from the last 10 years for a Systematic Review you wish to publish
• it may include concepts that do not have precise thesaurus terms & may require combinations of synonyms to capture all aspects of your research question.
  • e.g. you are doing PhD research & you are worried about missing any relevent studies

Literature searches often produce a large number of citations & require use of several databases.

Good search practice includes keeping a search diary or a document including details of your search strategy to allow others to reproduce your steps & get the same results.

Record your search strategies by logging details on:

• all database & any other sources you search - eg., Medline, Cochrane Library, Google Scholar, etc.
• note down journal titles that appear often during your searches to familiarize yourself with journals in your area of interest.
• which search terms you used (keywords, subject headings, phrases)
• any search techniques you applied (truncation, proximity, etc.)
• how you combined your search terms (AND/OR/NOT)
• the number of search results from each source & each strategy used.

Download the citations you have retrieved to a reference manager &/or excel spreadsheet to deduplicate citations if necessary.

PubMed Search Filter used to find Randomized Controlled Studies: These search strings can be added to your subject & keyword searches to limit your results to sensitive or sensitive and precise results depending on the type of research you are doing.

1. Sensitivity-Maximizing Version (2008 revision) - Maximizes recall. Preferred search for a Systematic Review on trials (exhaustive)

2. Sensitivity and Precision-Maximizing Version (2008 revision) - Provides a balance of recall and precision. Preferred for a Review or RCTs (not exhaustive)