Perhaps you should try some spelling variations:
"modified multiobjective optimization algorithm" » "modified multiobjective optimization algorithms", "modified multiobjective optimisation algorithm", "modified multiobjective estimation algorithm"
"modified risk optimizer algorithms" » "modified risk optimized algorithms", "modified risk optimized algorithm", "modified risk optimization algorithms", "modified bi1 optimizer 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 risk optimizer algorithms") OR ("modified multiobjective optimization algorithm"))~.
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