Perhaps you should try some spelling variations:
"modified orca approximation algorithm" » "modified orca approximation algorithms", "modified one approximation algorithm", "modified _ approximation algorithm", "modified time approximation algorithm"
"machines learning method algorithm" » "machine learning method algorithm", "active learning method algorithm", "mapping learning method algorithm", "machines learning mom algorithm", "machines learning methods algorithm", "machines graining methods algorithm", "machines learning emotion 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 method algorithm") or ("modified orca approximation algorithm"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("machines learning method algorithm") OR ("modified orca approximation algorithm")).
• Removing quotes may allow a broader search: (( machines learning method algorithm ) or ( modified orca approximation algorithm )).
• Adding a wildcard symbol may retrieve word variants: (("machines learning method algorithm") or ("modified orca approximation algorithm"))*.