Perhaps you should try some spelling variations:
"defined network optimization algorithms" » "defined network optimisation algorithm", "defined network estimation algorithms", "defined network estimation algorithm", "designed network optimization algorithms"
"modified rough approximation algorithm" » "modified rough approximation algorithms", "modified rough approximations algorithm", "modified one approximation algorithm"

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"defined network optimization algorithms\") OR (\"modified rough approximation algorithm\"))~".
• Removing quotes may allow a broader search: (( defined network optimization algorithms ) OR ( modified rough approximation algorithm ))~.
• Adding a wildcard symbol may retrieve word variants: (("defined network optimization algorithms") OR ("modified rough approximation algorithm"))*.