Perhaps you should try some spelling variations:
imputation techniques » implantation technique, augmentation techniques, segmentation techniques
section techniques » reduction techniques, reduction technique, vision techniques
access section » cross section
co imputation » co limitation
based access » based cross
based co » based code, based no2, based two

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 co imputation techniques ) or ( learning-based access section techniques ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( learning-based co imputation techniques ) OR ( learning-based access section techniques )).
• Adding a wildcard symbol may retrieve word variants: (( learning-based co imputation techniques ) or ( learning-based access section techniques ))*.