Perhaps you should try some spelling variations:
"learning-based co imputation techniques" » "learning-based co implantation technique", "learning-based co augmentation techniques", "learning-based co segmentation techniques", "learning-based co limitation techniques", "learning-based no2 imputation techniques", "learning-based two imputation techniques", "learning-based _ imputation techniques"
"learning-based code inhalation technique" » "learning-based code floatation technique", "learning-based code implantation technique", "learning-based code inhaler technique", "learning-based anode inhalation technique", "learning-based no2de inhalation technique", "learning-based twode inhalation technique", "learning-based _de inhalation 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 co imputation techniques") OR ("learning-based code inhalation technique"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"learning-based co imputation techniques\") OR (\"learning-based code inhalation technique\"))*".
• Removing quotes may allow a broader search: (( learning-based co imputation techniques ) OR ( learning-based code inhalation technique ))*.