Boolean operators are a tool for combining search terms. In the list below you find an overview of the operators. Pay attention to the influence of the selected interface language. Both capital and lower-case letters may be used.
Boolean operators | Outline | Example | ||
All interfaces | Dutch interface |
French interface | ||
and | en | et | All terms entered must be present in references found | communications and telephone |
or | of | ou | At least one of the terms entered must be present in references found | communications or telephone |
not | niet | pas | The term following operator 'not' may not feature in reference(s) found | communications not telephone |
near | nabij | pres | The terms preceding and following operator 'near' must both feature in references found, but there may be no more than 4 words between them. In which sequence terms feature does not matter. | communications near telephone |
You can combine several operators in a single query. Because of the processing sequence (first NEAR, then AND, then NOT, then OR), you have to pay attention in your query to the sequence of the search terms and the used Boolean operators. It is recommended to make use of parentheses to indicate in which sequence processing must take place; the operator(s) inside parentheses are processed first.
For example, if you search via methods Direct search or Advanced search you could use the following queries:
(vehicle or vehicles or automobile or automobiles) and ((suspension or suspensions) near (active or semi-active))
or by using truncation:
(vehicle$ or automobile$) and (suspension$ near *active) = (vehicle$ or automobile$) and suspension$ near *active