Perhaps you should try some spelling variations:
"modified adaptive approximation algorithms" » "modified time approximation algorithms", "modified passive approximation algorithms"
"modified objective optimization algorithm" » "modified multiobjective optimization algorithm", "modified objective optimization algorithms", "modified objective optimisation algorithm", "modified objective estimation algorithm"

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• Performing a fuzzy search may retrieve terms with similar spellings: (("modified adaptive approximation algorithms") or ("modified objective optimization algorithm"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("modified adaptive approximation algorithms") OR ("modified objective optimization algorithm"))*.
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