Perhaps you should try some spelling variations:
passiv » passive, passiver
passiven » passiveen, passiveren, passive
passiveren » passiveeren, passivereren, passivieren, passieren, passiver
passiverer » passiveerer, passivererer, passiverwerb, passivieren, passiver
massiv » massive

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 massiv) OR ((passiven OR passion) OR (passiveren OR passiverer))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((passiv or massiv) or ((passiven or passion) or (passiveren OR passiverer)))".
• Adding a wildcard symbol may retrieve word variants: ((passiv or massiv) or ((passiven or passion) or (passiveren OR passiverer)))*.