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