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