Perhaps you should try some spelling variations:
mitigation techniques » imputation techniques
reduction techniques » reduction technique, imputation techniques
3d reduction » _ reduction
k mitigation » _ mitigation, _ litigation
based 3d » based _, based co, based n
based k » based _, based n, based co

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 3d reduction techniques ) or ( learning-based k mitigation techniques ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( learning-based 3d reduction techniques ) OR ( learning-based k mitigation techniques )).
• Adding a wildcard symbol may retrieve word variants: (( learning-based 3d reduction techniques ) or ( learning-based k mitigation techniques ))*.