Perhaps you should try some spelling variations:
contract based » control based, content based, context based
study contract » study contracting, study context, study abstract
yang study » yang judy, arg study
young ghi » young choi, hong ghi, young get
yao yang » yang yang
based ad » based aid, based ads, based ai
ad young » a young, jae young, saw young

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

• Performing a fuzzy search may retrieve terms with similar spellings: (wan or wing) yao yang study contract based ad young ghi ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (wan OR wing) yao yang study contract based ad young ghi ;.
• Adding a wildcard symbol may retrieve word variants: (wan or wing) yao yang study contract based ad young ghi ;*.