Advanced Search Techniques

Boolean operators define the relationship between search terms.

• AND searches for all of the search terms. The AND operator limits the search because the sources in the results must contain both terms.
• OR searches for either of the search terms. The OR operator expands the search because the sources in the results can contain either term.
• NOT excludes the search term immediately after the NOT operator. The NOT operator limits the search because the sources in the results cannot include the term following the word NOT.

Example:
diabetes AND children = articles about children with diabetes
diabetes OR children = articles about either diabetes or children 
diabetes NOT children = articles about diabetes, but excludes articles mentioning children with diabetes

This diagram will show you how the Boolean operators limit or expand searches.

Image attribution: CC BY-SA 4.0 by Cecelia Vetter

For more help, watch this video on Using Boolean Operators:

Boolean Modifiers can be used to further refine your search. 

• The asterisk *, also called the wildcard or truncation, searches for all forms of the word stem.
  • For example, searching nurs* would return results for nurse, nurses, nursing, etc. 
  •  Searching for statistic* would return results for statistic, statistics, statistical, etc. 
• The parentheses () are used around OR statements to ensure the database recognizes which terms are encapsulated in the OR statement. 
  • For example, if you're expanding your search to encapsulate three similar keywords, you can put parentheses around the whole statement like so: (high school OR secondary school OR senior high school)
• Quotation marks " " are used to return results with the exact term inside the quotation marks.
  • For example, if you search "bird" you will only get results that contain the word "bird," but not words like birds or birding. 

Proximity searching is an advanced search strategy where you can search for multiple words near each other. It allows you to find where multiple search terms occur within a certain number of words from each other.

The proximity operators are composed of a letter (N or W) plus a number (to specify the number of words). The number cannot exceed 255.

The proximity operator is placed between the words that are to be searched:

• Near Operator (N): N5 finds the words if they are a maximum of five words apart from one another, regardless of the order in which they appear. For example, type tax N5 reform to find results that have a maximum of five words between the beginning and ending terms, that would match tax reform as well as tax that has been submitted for reform.

• Within Operator (W): W8 finds the words if they are within eight words of one another, in the order in which you entered them. For example, type tax W8 reform to find results that would match tax reform but would not match reform of income tax.

In addition, multiple terms can be used on either side of the operator. See the following examples:

• (tax OR tariff) N5 reform
• oil W3 (disaster OR clean-up OR contamination)
• (baseball OR football OR basketball) N5 (teams OR players)

Note: Boolean operators (AND, OR, NOT) are best entered in upper case to ensure they are treated as Boolean operators instead of literal words.

Adapted from EBSCO's How do I create a proximity search? documentation: