As a first point of call to find information, you should visit the National electronic Library for Health (NeLH). Hold your mouse here to see an example NeLH search.

To conduct a more comprehensive search however, you may need to look in databases such as Medline and the Cochrane Library - for which you will need to undertand some of the basic principles of searching.

Different databases and interfaces offer the functions listed below in different ways, but it is important to understand (and be able to apply) the principles.

• Textword searching - including use of truncation
  
• Thesaurus searching - finding the right term, exploding terms and using subheadings
  
• Boolean operators - using AND, OR, NOT
  
• Devising a search strategy - combining textwords, thesaurus terms and Boolean to produce a search strategy

Later on, we will see how to apply these principles to PubMed (free internet version of Medline) and the Cochrane Library.

Let us first look at these search principles in more detail.