Making
Searching More Precise With Boolean Operators
Boolean
searching allows
you to research a topic with greater precision by linking the
essential elements of your research question with the operators
and, or,
or not.
In this way you can broaden or narrow a search.
And
narrows a search because it asks that all sources in the results
list have each search term (two or more) in them. So if you were
to add and
medical
to a search for marijuana,
or hashish,
or cannabis,
you would limit your sources to those with marijuana
and medical,
or hashish and
medical,
or cannabis
and medical.
Here's an
example of the way and
would narrow this search.
Suppose that the database has 90 documents with the term medical
in them. If you join medical to the other three
terms with and,
you will get a maximum of 90 hits (sources in your results list)
and most likely many fewer since every document must have medical
and one of the other
three terms in it. Your results might be something like this.
medical
and marijuana 22 documents
medical and cannabis 6 documents
medical and hashish 3 documents
Your results list would have no more than 31 documents.
Not
allows you to narrow a search further
by eliminating what would be irrelevant hits. For example, for
a paper on legalizing marijuana, you can specify not
Canada thereby
eliminating any articles on legalizing marijuana in Canada.
