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Searching: Complex Searches

Detailed guide to searching tips and tricks

             Microscope left          COMPLEX SEARCHING (In Edit!)           

A complex search uses specific combinations of multiple terms to hone your search result to the desired outcome

Trawl to net lots of results        A Sensitve search is used to trawl for a wide variety of results        Trawler blue left

      A Specific search will pick out a much narrower selection      Find specific records             

You have done a simple search....Here are the possible stages for doing a complex search strategy. Look at tabs  for more information and links for each section


1: Identify terms                                   Help with finding all the relevant words for a comprehensive search 

2: Group  terms                                    Create an initial Search Strategy

3:  Select Sites and Databases            Choosing the best places to look for your particular enquiry

4: Create and Adapt Strategies            Tailoring  your search to each database

Review your terms each time. Consider alternative spellings. Wild-Cards permitted?.  Truncation available?   Keyword searching? Search fields?

5:  Run the searches                             Assemble your terms and enter. Make use of any specific features. 

6:  Modifying the initial search              Addressing issues of quality and quantity of results.

Too few? : Try combining fewer concepts  Too many?: Look at limits   - by date - by article type - by location...

7:  Assessing quality                              What is worth keeping? Working towards critical appraisal

8   Saving Results                                 The options available for storing, reviewing and referencing your articles 

9   Fuller Guidance:                               Resources that take you through all the stages:

Identifying Terms

    Try and identify as many relevant terms as possible. This  will help make the search more Sensitive     

      Try also to identify the most relevant terms. Using these could make the search more Specific  Find specific records

Try a Clinical Question:                                                                           

     Grouping your identified terms &  creating a question  can help you to focus    Practice Here     3 Clinical Questions   
Find out about Thesauri:  

     Authors often use different terms for the same topic, like: Heart attack / myocardial infarction /MI.  This can make searching hard. 
     However the database cataloguers group all such similar terms under a unique keyword. In Medline / Pubmed this is called a MESH term. (Medical Subject Heading).

     The MeSH headings are included on each record.  So if you know the right MesH headiing you can pick up a wider range of relevant articles.

     See a sample database record   Here.                                       Medline Database Record

     MH is the 'MeSH field. You may need to tweak your search to include this field in it.

     MeSH terms are arranged in  a hierarchy - like a family tree.  More? >>  Mesh Tutorial  

     Search For Mesh terms here on Pubmed site       
                                                                                      Searching for Mesh Terms

You might also like:

Other Sources  
Look in Systematic Reviews for search terms   Search Terms from Review
Look in published papers for key words            Keywords from Paper
Find Mesh Terms on Pubmed Papers              Mesh Link on PubMed result
Do simple searches on google                          Google Angiodema bar
A 'Target Phrase' might lead to answer you want.
                                                                               You can use OR (in caps!)  to use any alternative  terms in the phrase  See Google guide  (Section 4 )  for further tips.
- See alternative terms in the results.snippet         
Try Medical Dictioniaries                                      


Grouping Terms

    Correctly grouping  relevant alternative terms together can make the whole, or parts of the search more Sensitive     

      Correctly grouping very precise terms can make the end results  more Specific   Find specific records 


Create a Framework

Group your terms together  according to the different areas that frame your search.

Such frameworks may include sections such as: 

  • The Situation
  • The Actions
  • The Results
  • A Comparison

PICO is the best known one :  Patient Intervention Comparison  Outcome              

      Thumb other OICOs                                         Thumb Thames Guide    

   To read about others Click HERE                      Click HERE  for a blank PICO sheet                                'The Literature Search Process'                                                                                                                                                                        and example                                                                 Read more about using PICO itself                                                 


Group all similar Terms

Each  framework section may have several different terms. The similar terms must be grouped together.

Here's some terms to describe Older hypertensive men with Type 1 diabetes

Male Type 1 diabetes Elderly High blood pressure
Men Type 1 diabetic Aged Hypertension
  Insulin dependent diabetes mellitis    

Combine the Terms

  • First group any multiple equivalent terms with OR and use brackets.
  • Then  combine these groups - and any individual terms with AND

(Male OR Men) AND (Type 1 Diabetes OR Type 1 diabetic OR Insulin Dependent Diabetes Mellitis OR IDDM) AND Elderly AND ( High Blood Pressure OR Hypertension )

( You can do this automatically and then do a search with the  Search Whiteboard tool )

Further Help

                                  Tracking Evidence Thumb                                  Thumb Boolean Cheatsheet

Boolean logic :          For Quick Powerpoint intro download HERE            For more detailed explanation download HERE                   For summary sheet see HERE      


Adapting Strategies

Terms may be needed to modified, depending on the database used or to focus the search in particular area - like the title of an article

See the Tab 4


SELECT SITES  ( in draft)

Choosing where to look:

Choosing where to look depends on several factors:

  • What is the subject area?    What sort of query is it?       Who is it for?    What level of detail is required?    Do you want original material or synthesis ?   Published or unpublished ?   


Where to Look 5


Graphic Source:   See Notes below table

Guide to Resources
Source Comment

General Internet

A general search on the internet will often bring you up some initially apparently relevant results.   More so  if you have the skills to limit and hone your search terms. However you cannot guarantee that the most reliable information appears first nor that the information provided is accurate, current or unbiased, so you need to be quite savvy.  Google Scholar is a better site in this regard

Google: Better Searching 


Dedicated sites that either filter or search a subset of reliable information: Nice Evidence, Trip,, Patient UK  ( See where to look tab )

Point of care tools such as  Uptodate enable you to focus into solutions for clinical problems very quickly

Some specialisms have dedicated data bases, like PeDro for Physios. Professional Bodies and colleges also also have their own dedicated websites

Government departments.  Health and Safety, Environmental monitoring

If you are in a specialised field then it may be worth searching on a particular journal first only eg Journal of Clinical Oncology is often used in this way.


Notes on Graphic

This original graphic is entirely based on personal observation and opinion.
The aim is to cut text and represent the sort of sources that might me appropriate for some typical tasks.

It can be very easily edited.
 The original sheet is here. 
Please contact me if you have some improvements and suggestions 

General Internet:  Major search engines




IN EDIT  Nov '17                

Alternative spellings.

Some search engines do this automatically but some might use wild cards * or ?

 glyc?emic    may give glycemic andglycaemic

Stemming gives you all the variations of endings to a word but plurals are now often put in automatically

Prevent*  would get    prevent, prevents, preventing, prevention... 

You can search in different parts of the result, like Title, URL.Domain Name: Methods vary:

Trip uses title:    

 title:"Heart attack" 

Google uses   intitle:

intitle:"Myocardial Infarction"                    (Lower case, so space after colon )      

See   below for  a self-teach resource on Google with lots of useful hints and tips.

Coming Soon...

Coming soon


          'The Literature Search Process'                                                                  Excellent tabbed tutorial from Duke University Here

Thames guide to searching         Duke EBP tutorial

Recording Form and Example Here

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