One of the
things that will make you a better web searcher is
understanding
what you need to type in order to tell the
search engine exactly what you are
looking for.
There are two
categories of search operators: Boolean and non-Boolean
operators. An
operator is a word or symbol that you type in that gives the
search engine directions to help it know what to
search for. Using these operators
can narrow or widen your search, helping you
find web sites that may be useful to you.
You will have to
check out the individual search engines to find out which
operators work.
Boolean
Searching:
AND means
the search results must have both terms.
Often it is typed in
UPPER CASE, but not
always. AND decreases
the number of web sites that will be
found, narrowing in on specific topics.
Example: pollution AND water will look
for web sites about both
pollution and water.
OR means
the search results can have just one of the terms.
OR increases the number of web sites that will be found,
broadening
your search.
Example: pollution OR water will look
for web sites that mention
either pollution
or water.
NOT means
any result containing the second term will be excluded.
NOT decreases the number of web sites that will be found,
narrowing
your search.
Example: pollution NOT water will look
for web sites about pollution
that do not involve water. Warning: Be very careful about using NOT. If
the web site mentions water even once, it may
be left out. This could
rule out some very useful web sites. Likewise,
you must be careful when using
OR. You can end up with a huge number of sites to sort through.
Non-Boolean
Searching:
+ works like AND, making the term
required in the search results.
The + should
be placed directly in front of the search term without
any spaces.
Example: pollution +water will look for
web sites about pollution that
also mention water.
– works
like NOT and means to exclude the term
the - should be
placed directly in front of the search term without
any spaces.
Example: pollution –water will also look
for web sites about pollution
that do not involve water.
“ ” placed
around terms means the search engine will look for the exact
phrase.
Example: “water
pollution” will look for that exact phrase. This
can
make your search very specific.
Warning: Just as with the Boolean terms, you must be careful when
using -
that you do not eliminate web sites that might mention
the term you do not want, but are not really
about that term.
–water may eliminate web sites that are
about air pollution but
mention water pollution as well.
How
to find out which search operators to use:
Different web sites and search engines use
different systems, and you will
need to learn which search terms work best with
your particular search
engine.
Many web sites and search engines will tell you which to use if you
click on
buttons such as HELP or ADVANCED SEARCH or POWER
SEARCH or
SEARCH TIPS. They may also offer other
search limit options such as
letting you pick dates or languages. Explore your
favorite search engines to
find out what they can do!