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