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"
"modified learning estimation algorithm" » "modified learning emotion algorithm", "modified lighting estimation algorithm", "mobile learning estimation algorithm", "modified caging estimation algorithm"

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