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