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 objective optimization algorithm" » "modified multiobjective optimization algorithm", "modified objective optimisation algorithm", "modified objective estimation algorithm", "modified objective estimation algorithms"

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("modified _ optimization algorithms") or ("modified objective optimization algorithm"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified _ optimization algorithms") OR ("modified objective optimization algorithm")).
• Removing quotes may allow a broader search: (( modified _ optimization algorithms ) or ( modified objective optimization algorithm )).
• Adding a wildcard symbol may retrieve word variants: (("modified _ optimization algorithms") or ("modified objective optimization algorithm"))*.