Part I: Prepare search

I.3.4 Combining search terms

You can use Boolean operators to define your search more precisely. The notation of the operators can vary in the various information tools; please refer to the respective help texts.

Example: You are supposed to write a term paper on the topic "Crayfishes in the Baltic Sea Region".

AND operator

Example search	Krebse [crayfishes] AND Ostsee [Baltic Sea]
Effect	An intersection is formed - the number of hits is reduced
Meaning	The hit list contains documents in whose bibliographic description the term "crayfish" and the term "Baltic Sea" appears.

Linkage with AND: creation of an intersection

OR operator

Example search	Krebstier [crustacean] OR crayfish
Effect	A union set is formed - the hit list is expanded.
Meaning	The hit list includes documents whose bibliographic description contains the term "Krebstier" as well as documents whose bibliographic description contains the term "crayfish".

Linkage with OR: creation of a union set

NOT operator

Example search	crustacea NOT Bestimmungsbuch [identification book]
Effect	A difference set is formed - the number of hits is reduced.
Meaning	The hit list contains those documents in whose bibliographic description the term "crustacea" appears; those documents whose bibliographic description contains the term "Bestimmungsbuch" are sorted out.