Perhaps you should try some spelling variations:
"modified coverage approximation algorithms" » "modified average approximation algorithms"
"modified passive ventilation algorithms" » "modified passive estimation algorithms", "modified passive estimation algorithm", "modified passive convolution algorithms", "modified adaptive ventilation algorithms", "modified invasive ventilation 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 coverage approximation algorithms") OR ("modified passive ventilation algorithms"))~.
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