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 invasive evolution algorithm" » "modified invasive solution algorithm", "modified invasive evolutionary algorithm", "modified invasive convolution algorithms", "modified invasive ventilation algorithm", "modified passive 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 invasive evolution algorithm") OR ("modified df approximation algorithm"))~.
• Removing quotes may allow a broader search: (( modified invasive evolution algorithm ) or ( modified df approximation algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified invasive evolution algorithm") or ("modified df approximation algorithm"))*.