Perhaps you should try some spelling variations:
thanh nung » thanh tung, thanh hung, thanh dung
viet tach » viet sach, viet tech, viet thanh
dang nong » dang cong, hang nong, tang nong
doi viet » dai viet, hoi viet, oi viet
nung cao » nang cao, nhung cau, quang cao
nong dan » cong dan, nong san, nguong dan
toan cao » toan ban, toan tap

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 - thanh nung cao dang nong dan ((van ban) or (toan cao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi viet tach - thanh nung cao dang nong dan ((van ban) OR (toan cao)).
• Adding a wildcard symbol may retrieve word variants: doi viet tach - thanh nung cao dang nong dan ((van ban) or (toan cao))*.