Paso del Norte Institute for Healthy Living: Advanced Searching

The terms you use will greatly affect what results you get. If your search terms are too specific, you won't get enough results.  If they are too broad, you will get too many results.

We are given this research question:  what is the effect of exercise on recovery from a heart attack type? 

• Don't type that question into a database, the databases can't parse whole sentences.
  • find the main terms
    • effect, exercise, recovery, heart attack
• look for synonyms, some potential results might use a different term if it is an option
  • effect's synonyms include consequences and results
  • the medical name for a heart attack is myocardial infarction, so you would want to use both terms
• depending on your research question, you may want to look for superterms or subterms. 
  • if you are looking for a category, you may add elements of the category. e.g., if you are looking for the prevalence STDS, you can search with multiple STDS.
  • if you are looking for an element, you may add it's larger category, e.g., if you are looking for information on the effectiveness of Lipitor on high cholesterol, you can widen it to the effectiveness of statins in general.

Use Boolean operators to combines terms when you search with more than one term.

When you search similar terms, you want to use OR.  OR will get results that use at least one of the terms.

When you search different terms, you want to use AND.  AND will get results that use all of the terms.

When you don't want results with a term, you want to use NOT.  NOT will remove results that use that term.

You can use more than one operator.
Say you want information on heart attack recovery.  The clinical term for heart attack is myocardial infarction, so you want to use that as well.  Since they are similar terms, you combine heart attack and myocardial infarction with an OR.  Recovery is different, and we want results that deal with both ideas. So now we can search for (Heart attack OR myocardial infarction) AND recovery. 

When combining different types of operators, you need to use parentheses around groupings. "heart attack OR myocardial infarction AND recovery" is ambiguous.
(Heart attack OR myocardial infarction) AND recovery

gets different results than heart attack OR (myocardial infarction AND recovery)

Using multiple search terms properly combined with boolean operators will skillfully refine your search, but there are times when skillful removal is not necessary.  One can remove large numbers of unwanted results with limiters.

Research in health can quickly become outdated, but all databases will let you set a date range, and anything outside that range will not appear.  For instance, Pubmed offers this quick date limiter, with one click you can get rid of anything more than 5 years.  And with a few more you can set a custom range, e.g.,  if you want articles that are less than 3 years old.