Perhaps you should try some spelling variations:
"modified coverage approximation algorithms" » "modified average approximation algorithms"
"modified based optimisation algorithm" » "modified based optimization algorithms", "modified based estimation algorithm", "modified based estimation algorithms", "modified game optimization algorithm", "modified male optimisation algorithm"

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• Performing a fuzzy search may retrieve terms with similar spellings: (("modified coverage approximation algorithms") OR ("modified based optimisation algorithm"))~.
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