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