Perhaps you should try some spelling variations:
"modified df approximation algorithm" » "modified df approximation algorithms", "modified _ approximation algorithm", "modified one approximation algorithm", "modified time approximation algorithm", "modified adam approximation algorithm", "modified bi1 approximation algorithm"
"modified learning method algorithm" » "mobile learning method algorithm", "modified caging method algorithm", "modified learning mom algorithm", "modified learning methods algorithm", "modified graining methods algorithm", "modified learning emotion 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: (("modified learning method algorithm") OR ("modified df approximation algorithm"))~.
• Removing quotes may allow a broader search: (( modified learning method algorithm ) or ( modified df approximation algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified learning method algorithm") or ("modified df approximation algorithm"))*.