Perhaps you should try some spelling variations:
optimization algorithms » optimisation algorithm, estimation algorithms, estimation algorithm
approximation algorithm » approximation algorithms
location optimization » allocation optimization, static optimization
time approximation » one approximation, _ approximation
modified location » modified carbon
modified time » modified bi1, modified male

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