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.

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