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