Perhaps you should try some spelling variations:
passiv » passive, massiv, passiven
passiverer » passiveerer, massiverer, passivenerer, passiverwerb, passivieren, passiver
massiver » massive, passiver, massively
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 (passiverer OR (massiver OR massiven))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(passiv or (passiverer or (massiver OR massiven)))".
• Adding a wildcard symbol may retrieve word variants: (passiv or (passiverer or (massiver OR massiven)))*.