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