Perhaps you should try some spelling variations:
"Made improve learning" » "Made improved learning", "Made improving learning", "Made immersive learning"
"Made simple learning" » "Made complex learning"
"made ensemble learning" » "image ensemble learning", "maps ensemble learning", "face ensemble learning"
made improve » mode improved, trade improve, care improve

Try widening your search to All Fields.

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: (((("Made simple learning") OR ("Made improve learning"))) OR ("made ensemble learning")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"Made simple learning\") OR (\"Made improve learning\"))) or (\"made ensemble learning\"))".
• Removing quotes may allow a broader search: (((( Made simple learning ) OR ( Made improve learning ))) or ( made ensemble learning )).
• Adding a wildcard symbol may retrieve word variants: (((("Made simple learning") OR ("Made improve learning"))) or ("made ensemble learning"))*.