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