Perhaps you should try some spelling variations:
mitigation techniques » imputation techniques
simulation techniques » imputation techniques, segmentation techniques, inhalation technique
no2 mitigation » _ mitigation, error mitigation
3d simulation » _ simulation, a simulation, mri simulation
based no2 » based co, based n
based 3d » based _, based co, based k

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( learning-based no2 mitigation techniques ) OR ( learning-based 3d simulation techniques ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( learning-based no2 mitigation techniques ) OR ( learning-based 3d simulation techniques ))".
• Adding a wildcard symbol may retrieve word variants: (( learning-based no2 mitigation techniques ) OR ( learning-based 3d simulation techniques ))*.