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