Perhaps you should try some spelling variations:
passiv » massiv
passiven » massiven, passion
passive » massive
passiverer » massiverer, passiverwerb, passivieren, passieren, passivelyer, passierter
passiver » massiver, passively, passiert

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 passiven) OR passive) OR (passiverer OR passiver))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((passiv OR passiven) or passive) or (passiverer or passiver))*".