Perhaps you should try some spelling variations:
thanh trong » thanh trung, tranh trong, hanh trong
hieu lang » chieu sang, hieu quang, nhieu tang
trong nam » thong nam, trong lam, trong cac
dung cong » dung trong
cong danh » cuong danh, cong dan, cong thanh
hoc hieu » hoc thieu, hoc hien, doc hieu
nam dung » nam vung, nam dong, am dung

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu lang - thanh trong nam dung cong danh ((toan ban) or (van ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - thanh trong nam dung cong danh ((toan ban) OR (van ban)).
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - thanh trong nam dung cong danh ((toan ban) or (van ban))*.