Perhaps you should try some spelling variations:
"learning-based n reduction techniques" » "learning-based n reduction technique", "learning-based n imputation techniques", "learning-based _ reduction techniques", "learning-based _ prediction techniques", "learning-based _ production techniques", "learning-based k reduction techniques", "learning-based 3d reduction techniques"
"learning-based no2 inhalation technique" » "learning-based no2 floatation technique", "learning-based no2 implantation technique", "learning-based no2 imputation techniques", "learning-based _ inhalation technique", "learning-based co inhalation technique", "learning-based _o2 inhalation technique", "learning-based ko2 inhalation technique", "learning-based 3do2 inhalation technique"

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (("learning-based no2 inhalation technique") OR ("learning-based n reduction techniques"))~.
• Removing quotes may allow a broader search: (( learning-based no2 inhalation technique ) or ( learning-based n reduction techniques ))~.
• Adding a wildcard symbol may retrieve word variants: (("learning-based no2 inhalation technique") or ("learning-based n reduction techniques"))*.