Perhaps you should try some spelling variations:
"learning-based series augmentation techniques" » "learning-based series segmentation techniques", "learning-based series imputation techniques", "learning-case series augmentation techniques", "learning-based sers augmentation techniques", "learning-based devices augmentation techniques"
"learning-based co reduction techniques" » "learning-based co reduction technique", "learning-based co imputation techniques", "learning-based _ reduction techniques", "learning-based h2o2 reduction techniques", "learning-based closed reduction techniques", "learning-based code reduction techniques", "learning-based no2 reduction techniques", "learning-based two reduction techniques"

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 reduction techniques") or ("learning-based series augmentation techniques"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("learning-based co reduction techniques") OR ("learning-based series augmentation techniques"))*.
• Removing quotes may allow a broader search: (( learning-based co reduction techniques ) or ( learning-based series augmentation techniques ))*.