Perhaps you should try some spelling variations:
"learning-based two imputation techniques" » "learning-based two implantation technique", "learning-based two augmentation techniques", "learning-based two segmentation techniques", "learning-based tool imputation techniques", "learning-based co imputation techniques"
"learning-based no2 inflation technique" » "learning-based no2 inhalation technique", "learning-based no2 implantation technique", "learning-based no2 mitigation techniques", "learning-based roll inflation technique", "learning-based _ inflation technique", "learning-based k inflation technique", "learning-based co inflation technique", "learning-based n inflation technique"

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 two imputation techniques") OR ("learning-based no2 inflation technique"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"learning-based two imputation techniques\") OR (\"learning-based no2 inflation technique\"))".
• Removing quotes may allow a broader search: (( learning-based two imputation techniques ) OR ( learning-based no2 inflation technique )).
• Adding a wildcard symbol may retrieve word variants: (("learning-based two imputation techniques") OR ("learning-based no2 inflation technique"))*.