Perhaps you should try some spelling variations:
"certified network approximation algorithm" » "certified network approximation algorithms", "verified network approximation algorithm"
"modified allocation estimation algorithms" » "modified allocation optimization algorithms", "modified motion estimation algorithms", "modified allocation estimation algorithm", "modified allocation optimisation algorithm"

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("modified allocation estimation algorithms") or ("certified network approximation algorithm"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified allocation estimation algorithms") OR ("certified network approximation algorithm")).
• Removing quotes may allow a broader search: (( modified allocation estimation algorithms ) or ( certified network approximation algorithm )).
• Adding a wildcard symbol may retrieve word variants: (("modified allocation estimation algorithms") or ("certified network approximation algorithm"))*.