Perhaps you should try some spelling variations:
hieu tinh » chieu tinh, lieu tinh, kieu tinh
nang cong » nang song, dang cong, bang cong
cong vang » cong lang, cong quang, cong ngang
doc hieu » toc thieu, hoc thieu, hoc hien
cung cua » chung cua, dung cua, cong cua
hung chu » nhung chu, hung thu, chung chou
vang van » dang van, tang van, lang van

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu tinh - manh ((cung cua) or (hung chu)) nang cong vang van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu tinh - manh ((cung cua) OR (hung chu)) nang cong vang van ban.
• Adding a wildcard symbol may retrieve word variants: doc hieu tinh - manh ((cung cua) or (hung chu)) nang cong vang van ban*.