Undertaking a literature search

It is possible to undertake a simple literature search using Google or Google Scholar. This can be very inefficient as most entries will not be journal articles but may be general postings or blogs with little or no evidence base. It is best to search in a standard literature database such as Medline (or its sister Pubmed), Embase, AMED, CINAHL, PsycINFO, TRIP, BNI, Cochrane library, HMIC, PEDro etc..

Many databases such as Medline and Embase require a standardised approach to searches using defined terms.  Textwords can be used along with controlled vocabulary terms (MeSH, EMTREE) from the relevant thesaurus.  These have to be structured and linked using fields, additional parametrics or Boolean operators (AND, OR, NOT) (eg. firemen AND smoke NOT cigarette).  Text words can be truncated with defined characters to include plurals etc. (fire*3 will pick up firemen and fireman but not firefighter).  This is technical and complicated.

Fortunately the PubMed database which is freely available on the internet from the US National Library of Medicine National Institutes of Health does all this for you.  It has an inbuild algorithm that automatically adds and converts a simple group of text words into the required search terminology.  Try it by typing in ‘firefighter cardiovascular fitness’ and look on the right hand side under ‘Search details’ to see how this works.  Unfortunately some NHS IT systems won’t allow access to the PubMed system because it is a ‘foreign government website’.  You may be able to persuade your local IT controller to give you access.

Look at the abstract.  You can usually determine the journal, authors and their academic institute, the nature of the study, and key outcomes.  This should give a reasonable idea of the quality of the study and its relevance to the question you want to answer.  Increasingly the full text of papers is available on the internet.  These are generally on the host journal website and also available on the PubMedCentral database.