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

Try widening your search to All Fields.

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("modified multiobjective optimization algorithms") or ("modified channel estimation algorithms"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified multiobjective optimization algorithms") OR ("modified channel estimation algorithms")).
• Removing quotes may allow a broader search: (( modified multiobjective optimization algorithms ) or ( modified channel estimation algorithms )).
• Adding a wildcard symbol may retrieve word variants: (("modified multiobjective optimization algorithms") or ("modified channel estimation algorithms"))*.