Perhaps you should try some spelling variations:
"modified _ optimization algorithmssss" » "modified _ optimisation algorithm", "modified _ optimisation algorithmsss", "modified _ estimation algorithmssss", "modified _ estimation algorithmsss"
"modified parameter optimization algorithms" » "modified parameter optimisation algorithm", "modified parameter estimation algorithms", "modified parameter estimation algorithm", "modified parameters optimization algorithms"

Try widening your search to All Fields.

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