Perhaps you should try some spelling variations:
"modified multiobjective approximation algorithms" » "modified multiobjective optimization algorithms"
"modified model estimation algorithm" » "modified pose estimation algorithm", "modified cover estimations algorithm", "modified motion estimation algorithm", "modified male estimation algorithm"

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• Performing a fuzzy search may retrieve terms with similar spellings: (("modified multiobjective approximation algorithms") OR ("modified model estimation algorithm"))~.
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