Perhaps you should try some spelling variations:
passiv » passive, massiv, passiven
passiverwerb » passiveerwerb, massiverwerb, passivenerwerb, passiverer
passieren » passiert, passiven
massiven » massive, passiven, massively

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: ((passiv OR (passieren OR passiverwerb)) OR massiven).
• Adding a wildcard symbol may retrieve word variants: ((passiv or (passieren or passiverwerb)) or massiven)*.