Perhaps you should try some spelling variations:
mathematika » mathematica, mathematicae, mathematikum
mathematicala » mathematicals, mathematicaland, mathematically, mathematicsa
mathematical » mathematics
mathematikers » mathematikern, mathematiklernen
mathematiklehrer » mathematikern

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: (((mathematika OR mathematicala) OR (mathematik OR mathematical)) OR (mathematikers OR (mathematiklehrer OR mathematiker))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((mathematika or mathematicala) or (mathematik OR mathematical)) or (mathematikers or (mathematiklehrer or mathematiker)))".
• Adding a wildcard symbol may retrieve word variants: (((mathematika or mathematicala) or (mathematik OR mathematical)) or (mathematikers or (mathematiklehrer or mathematiker)))*.