Perhaps you should try some spelling variations:
"mathematical modelsing" » "mathematical modeling", "mathematical modelling", "mathematically modelling", "mathematical modelssing", "mathematical modelingsing", "mathematical methodssing"
"mathematical model" » "mathematical models", "mathematical modeling", "mathematical methods"

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: (("mathematical model") OR ("mathematical modelsing")).
• Removing quotes may allow a broader search: (( mathematical model ) or ( mathematical modelsing )).
• Adding a wildcard symbol may retrieve word variants: (("mathematical model") or ("mathematical modelsing"))*.