Perhaps you should try some spelling variations:
"modified multiobjective estimation algorithm" » "modified multiobjective optimization algorithm"
"modified sphere estimation algorithms" » "modified sphere optimization algorithms", "modified sphere optimisation algorithm", "modified sphere approximation algorithms", "modified pose estimation algorithms"

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

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