Perhaps you should try some spelling variations:
"modified coverage approximation algorithms" » "modified average approximation algorithms"
"modified a optimisation algorithm" » "modified a optimization algorithms", "modified a estimation algorithm", "modified a estimation algorithms", "modified _ optimisation algorithm", "modified _ optimization algorithm", "modified game optimization algorithm", "modified df optimisation algorithm", "modified adam optimisation algorithm"

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("modified coverage approximation algorithms") or ("modified a optimisation algorithm"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified coverage approximation algorithms") OR ("modified a optimisation algorithm")).
• Removing quotes may allow a broader search: (( modified coverage approximation algorithms ) or ( modified a optimisation algorithm )).
• Adding a wildcard symbol may retrieve word variants: (("modified coverage approximation algorithms") or ("modified a optimisation algorithm"))*.