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