Learn to use Boolean "AND," "OR," and "NOT" operators to
make your Web searches less frustrating. Booleans let you narrow your search
criteria by specifying that retrieved pages must contain more than one search
term (that's the AND operator), must contain at least one of several search
terms (OR), or must not contain a certain term (NOT). Unfortunately, not all
search engines offer Boolean searching, and those that do implement it in
different ways.
AltaVista's Advanced Text Search does Booleans the old fashioned
way: cocaine AND mexico AND NOT ("New Mexico" OR soccer OR football
OR baseball) will find items that mention cocaine and the nation Mexico,
while excluding anything about the state New Mexico, sports, and cocaine-using
athletes. (Note the quotation marks around New Mexico. That tells AltaVista
that New Mexico is a string--that is, those words must appear
together.)
HotBot
can interpret that expression, but its
Advanced Search page makes it easy with the "Look For" pop-up
menu, which includes "all the words" and "any of the words" as choices, and
the "Word Filter" pop-up, with choices for "must contain," "should contain,"
and "must not contain."
Google takes a different approach: It assumes an AND between
all search elements, does not support OR at all, and will perform a NOT if
you prepend a minus sign to a term. So if you're searching for cocaine
AND mexico AND NOT soccer at AltaVista and decide to try the same query
at Google, remember to use cocaine mexico -soccer.
Tomorrow: Nichy searches.
