Perhaps you should try some spelling variations:
wang yang » wang yan, wang yanling
dong bin » dong sin, dong di, dann bin
ein text » ein test, main text, von text
pre text » pre test, core text, die text
yang duc » yang du, sang duck, yang di
dang » dan, lang, dans
hai » hadi, haji, hari

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 liang) OR (wang yang))) OR (dong bin)) ya ((ein text) OR (pre text)) yang duc dang hai ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((wang liang) OR (wang yang))) or (dong bin)) ya ((ein text) or (pre text)) yang duc dang hai ;~".
• Adding a wildcard symbol may retrieve word variants: ((((wang liang) OR (wang yang))) or (dong bin)) ya ((ein text) or (pre text)) yang duc dang hai ;*.