Perhaps you should try some spelling variations:
study gender » study under, studying gender, student gender
david young » david loundy
study gene » study genetic, study agency
mark david » mare davide, parker david
yang yang » wang yang, wang yan
young ghi » young choi, hong ghi, young get
yan yang » yao yang, dan yang, tan yang

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: (wing OR wan) ((yan yang) OR (yang yang)) ((study gene) OR (study gender)) mark david young ghi ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(wing or wan) ((yan yang) or (yang yang)) ((study gene) OR (study gender)) mark david young ghi ;~".
• Adding a wildcard symbol may retrieve word variants: (wing or wan) ((yan yang) or (yang yang)) ((study gene) OR (study gender)) mark david young ghi ;*.