Perhaps you should try some spelling variations:
hieu tinh » chieu tinh, lieu tinh, kieu tinh
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong san, cong tan, huong dan
dan chan » dan gian, dan ca, van chat
va hang » van hang, va nang, va hanh
va lang » va nang, hoa lang
chan tu » phan tu, han tu, chon tu

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 - canh tranh ((va hang) or (va lang)) cong dan chan tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu tinh - canh tranh ((va hang) OR (va lang)) cong dan chan tu.
• Adding a wildcard symbol may retrieve word variants: doc hieu tinh - canh tranh ((va hang) or (va lang)) cong dan chan tu*.