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

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