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

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 sphere optimizer algorithms") OR ("modified multiobjective optimization algorithms"))~.
• Removing quotes may allow a broader search: (( modified sphere optimizer algorithms ) or ( modified multiobjective optimization algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified sphere optimizer algorithms") or ("modified multiobjective optimization algorithms"))*.