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

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