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