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