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