Perhaps you should try some spelling variations:
causing human » using human, reusing human, changing human
leading human » learning human, healing human, regarding human
income scale » income share, income shares
scale case » scalar case
case young » east young, jae young, wage young
young ghi » young choi, hong ghi, young get

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: (wan OR lang) yan ((leading human) OR (causing human)) income scale case young ghi ;~.
• Adding a wildcard symbol may retrieve word variants: (wan or lang) yan ((leading human) or (causing human)) income scale case young ghi ;*.