4. How do I search for the evidence?
4.5. Search tips
5.5 Search tips
When searching bibliographic databases, it’s important to remember that the database will only search for what you tell it to search for.
If you’re looking for resources on different types of livestock and use the search term ‘livestock’, the database won’t know that you’re interested in searching for cattle, sheep, goats, and poultry, unless you use those as search terms.
Be specific in your searches.
It is good practice to search for each concept separately. Having done this and perused the results allows verification that the terms retrieve relevant results for each concept. Then combine the individual concepts into a single result representing your (S)PICO . In most databases this is accomplished by using the Advanced search function or the Search History. These allow you to see the previous searches and results and to combine, recombine and edit them.
This has the advantage of enabling you to see the number of search results each concept gets.
That might help you to refine your search terms!
Boolean operators allow you to build your search up term by term...
…and then combine these terms in a variety of different ways, depending on how useful the results are.
Useful features you can use when searching
Truncation – This usually uses the symbol asterisk * at the end of a search term. This allows you to search for all possible endings, e.g. therap* will find therapy, therapies, therapeutic, etc.; diet* will find diet, diets, dietary, etc.
Proximity searching using ADJn, NEAR/n, NEXT – These work best when searching closely related words that you would expect in a paragraph, e.g. therap* NEAR diet*
Wildcards – This usually uses the question mark symbol ? to replace a letter within a word, e.g. an?esthesia will retrieve anaesthesia and anesthesia.
The symbols and functions for wildcards and truncation vary between different databases and search tools.
Check the help pages for each database to see what they support and use before starting your search.
For instance, Google doesn’t support truncation with an asterisk; instead it truncates automatically using stemming algorithms. However, asterisks can be used in Google as wildcards.
You can use these features to ensure that searches are comprehensive.
For example, when searching for information on cattle, a comprehensive search could be:
(cow OR cows OR cattle OR calf OR calves OR bovin* OR bovid* OR steer OR steers OR freemartin)