Perhaps you should try some spelling variations:
"modified multiobjective optimizer algorithms" » "modified multiobjective optimization algorithms", "modified multiobjective optimized algorithms", "modified multiobjective optimized algorithm"
"modified sphere estimation algorithms" » "modified sphere estimation algorithm", "modified sphere optimization algorithms", "modified sphere optimisation algorithm", "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 optimizer algorithms") OR ("modified sphere estimation algorithms"))~.
• Removing quotes may allow a broader search: (( modified multiobjective optimizer algorithms ) or ( modified sphere estimation algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified multiobjective optimizer algorithms") or ("modified sphere estimation algorithms"))*.