Operators

The software of the German Research Portal supports a variety of operators. By using these operators,compound searches can be specified. For this, the operators can be used together to formulate a complex topic. As a first step, the operators will be described separately:

AND or missing   The and-operator AND requires that the word in front of it and the word behind will both be found in the document. Example: laser AND plasma searches for documents with both words laser and plasma in them.
- or NOT The not-operator - requires that the word in front of it is in the document, but the word behind the operator must not be in that document. Example: laser - printer searches for documents which include the word laser, but not the word printer.
OR The or-operator OR can be used to specify several possibilities. Example: printer OR laserprinter searches for documents, which include the word printer or the word laserprinter or both.
" " The String-operator " gives you the possibility to search for an exact phrase. All words of the string must be in the document in a series and in the specified order. Example: If you search for to be or not to be you will only find documents which include this quotation.
( ) The bracket-operators ( and ) give you the possibility to change the normal priority of operators (see below). The expression in brackets will be evaluated first. You can use as many levels of brackets as youn like. Example: laser - (printer OR laserprinter) searches fot documents including the word laser but neither the word printer nor the word laserprinter.
* The endings-operator * enables you to automatically search for additional words with common endings. Example: laser* searches automatically for laser, lasers too.

Important for the correct usage of operators is their priority. The operators will be evaluated in this priority.