Perhaps you should try some spelling variations:
passiver » passive, passiven, passively
passiveren » passiveen, passivenen, passivelyen, passieren, passiverer, passiven
passivieren » passivierende, passivierung, passieren
passivene » passiven, passiveand, passiverer

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((passiver OR (passion OR (passiveren OR passivieren))) OR passivene).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((passiver or (passion or (passiveren OR passivieren))) or passivene)".
• Adding a wildcard symbol may retrieve word variants: ((passiver or (passion or (passiveren OR passivieren))) or passivene)*.