Perhaps you should try some spelling variations:
approximation algorithm » approximation algorithms
optimization algorithms » optimisation algorithm, estimation algorithms, estimation algorithm
response approximation » one approximation, response association
market optimization » game optimization, parameter optimization, market capitalization

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: (( response approximation algorithm ) OR ( market optimization algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (( response approximation algorithm ) or ( market optimization algorithms ))*.