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