Perhaps you should try some spelling variations:
"modified network optimization algorithm" » "modified network optimization algorithms", "modified network optimisation algorithm", "modified network estimation algorithm", "certified network optimization algorithm", "defined network optimization algorithm", "modified near optimization algorithm"
"modified df approximation algorithms" » "modified _ approximation algorithms", "modified one approximation algorithms", "modified time approximation algorithms", "modified adam approximation algorithms", "modified bi1 approximation algorithms"

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 df approximation algorithms") OR ("modified network optimization algorithm"))~.
• Removing quotes may allow a broader search: (( modified df approximation algorithms ) or ( modified network optimization algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified df approximation algorithms") or ("modified network optimization algorithm"))*.