Perhaps you should try some spelling variations:
optimisation algorithm » optimization algorithms, estimation algorithm, estimation algorithms
time approximation » one approximation, _ approximation
game optimisation » game optimization, stage optimization, _ optimisation
modified time » modified bi1, modified male
modified game » modified male, modified adam

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "(( modified time approximation algorithms ) OR ( modified game optimisation algorithm ))~".
• Adding a wildcard symbol may retrieve word variants: (( modified time approximation algorithms ) OR ( modified game optimisation algorithm ))*.