Perhaps you should try some spelling variations:
viet tach » viet sach, viet tech, viet thanh
doi viet » dai viet, hoi viet, oi viet
cong tac » cong ty
tac toan » tap toan, tam toan, hach toan
toan cau » toan cao, toan ban, toan tap
cua van » cua ban, cua vat, cua can
cua dan » cua dang, cua ban, ca dan

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi viet tach - canh tranh ((cua van) or (cua dan)) cong tac toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi viet tach - canh tranh ((cua van) OR (cua dan)) cong tac toan cau.
• Adding a wildcard symbol may retrieve word variants: doi viet tach - canh tranh ((cua van) or (cua dan)) cong tac toan cau*.