Perhaps you should try some spelling variations:
"modified objective optimization algorithms" » "modified objective optimisation algorithm", "modified objective estimation algorithms", "modified objective estimation algorithm", "modified multiobjective optimization algorithms"
"modified based gradation algorithm" » "modified based predation algorithm", "modified based estimation algorithm", "modified based evaluation algorithm", "modified based prediction algorithm", "modified male gradation 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 based gradation algorithm") OR ("modified objective optimization algorithms"))~.
• Removing quotes may allow a broader search: (( modified based gradation algorithm ) or ( modified objective optimization algorithms ))~.
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