Perhaps you should try some spelling variations:
numerische mathematical » numerische mathematik, numerical mathematical, numerischen mathematik
international serious » international services, international religious, international settings
numerical mathematics » industrial mathematics, general mathematics, numerische mathematik

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: international serious of ((numerical mathematics) OR (numerische mathematical)).
• Adding a wildcard symbol may retrieve word variants: international serious of ((numerical mathematics) or (numerische mathematical))*.