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