Perhaps you should try some spelling variations:
"modified _ optimization algorithm" » "modified _ optimization algorithms", "modified _ optimisation algorithm", "modified _ estimation algorithm"
"modified objective estimation algorithmss" » "modified objective estimation algorithms", "modified objective estimation algorithm", "modified objective optimization algorithms", "modified objective optimization algorithmss", "modified objective allocation algorithmss"

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 algorithm") OR ("modified objective estimation algorithmss"))~.
• Removing quotes may allow a broader search: (( modified _ optimization algorithm ) or ( modified objective estimation algorithmss ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified _ optimization algorithm") or ("modified objective estimation algorithmss"))*.