Perhaps you should try some spelling variations:
"modified multiobjective estimation algorithms" » "modified multiobjective optimization algorithms", "modified multiobjective estimation algorithm", "modified multiobjective approximation algorithms"
"modified channel optimisation algorithm" » "modified channel optimization algorithms", "modified channel estimation algorithm"

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 channel optimisation algorithm") OR ("modified multiobjective estimation algorithms"))~.
• Removing quotes may allow a broader search: (( modified channel optimisation algorithm ) or ( modified multiobjective estimation algorithms ))~.
• Adding a wildcard symbol may retrieve word variants: (("modified channel optimisation algorithm") or ("modified multiobjective estimation algorithms"))*.