Perhaps you should try some spelling variations:
passiven » passive, passion
passiveren » passivieren, passiverer, passiver
massigeren » massiger, massigen, massivere
passiveeren » passivieren, passiverer, passivierende
passieren » passiert
passiveeeren » passivieren, 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: (passiven OR (passiveren OR (massigeren OR ((passiveeren OR passieren) OR passiveeeren)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(passiven or (passiveren or (massigeren or ((passiveeren OR passieren) or passiveeeren))))".
• Adding a wildcard symbol may retrieve word variants: (passiven or (passiveren or (massigeren or ((passiveeren OR passieren) or passiveeeren))))*.