Perhaps you should try some spelling variations:
approximation algorithm » approximation algorithms
ventilation algorithms » estimation algorithms, estimation algorithm, convolution algorithms
passive ventilation » adaptive ventilation, invasive ventilation
one approximation » time approximation, _ approximation, rough approximations
modified passive » modified adaptive
modified one » modified male, modified near, modified orca

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "(( modified passive ventilation algorithms ) OR ( modified one approximation algorithm ))~".
• Adding a wildcard symbol may retrieve word variants: (( modified passive ventilation algorithms ) OR ( modified one approximation algorithm ))*.