Perhaps you should try some spelling variations:
germany gender » german gender, germany under, germany der
gender wage » gender based
derk 2012 » drk 2012, debt 2012, week 2012
yang jui » yang judy, yang xi, yang yi
wage tan » wage tax, wage gain, wage plan
hong gun » hyoung gun, thong guan, hong gang
wang » wing, wan, lang

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: ((((wang yan) OR (yang jui))) OR (yang di))derk 2012 germany gender wage tan hong gun ;~.
• Adding a wildcard symbol may retrieve word variants: ((((wang yan) or (yang jui))) or (yang di))derk 2012 germany gender wage tan hong gun ;*.