Perhaps you should try some spelling variations:
"modified network approximation algorithm" » "modified network approximation algorithms", "certified network approximation algorithm", "defined network approximation algorithm", "modified near approximation algorithm"
"modified objective allocation algorithms" » "modified objective estimation algorithms", "modified objective 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 network approximation algorithm") OR ("modified objective allocation algorithms"))~.
• Removing quotes may allow a broader search: (( modified network approximation algorithm ) or ( modified objective allocation algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified network approximation algorithm") or ("modified objective allocation algorithms"))*.