Perhaps you should try some spelling variations:
"learning-based two floatation techniques" » "learning-based two floatation technique", "learning-based two imputation techniques", "learning-based two inhalation technique", "learning-based _ floatation techniques", "learning-based tool floatation techniques", "learning-based co floatation techniques"
"learning-based data imputation technique" » "learning-based data imputation techniques", "learning-based data implantation technique", "learning-based data floatation 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 data imputation technique") OR ("learning-based two floatation techniques"))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"learning-based data imputation technique\") OR (\"learning-based two floatation techniques\"))*".
• Removing quotes may allow a broader search: (( learning-based data imputation technique ) OR ( learning-based two floatation techniques ))*.