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