Perhaps you should try some spelling variations:
hieu tinh » chieu tinh, lieu tinh, kieu tinh
doc hieu » toc thieu, hoc thieu, hoc hien
hoa lang » hoa dan, hoa van
cong dan » cong san, huong dan, cong dong
cong tan » cong tac, cong san, cong thanh
toan cao » toan ban, toan tap
va lang » va nang

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