Perhaps you should try some spelling variations:
passiv » passive, passiven, passiver
passivere » passiveere, passivenere, passiverere, passiverer, passiver, massivere
massiv » massive
aktivierende » aktivierenden, aktivieren, motivierende

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