Perhaps you should try some spelling variations:
nang hang » nang sang, hang hang, cang thang
dung cong » dung trong
chi sach » chinh sach, chieu sach, co sach
cong dan » cong san, cong tan, huong dan
than cao » toan cao, than cap, than sao
thai cao » tai cao, thoai cac, thuat cao
doi chi » doi khi
va dung » van dung, va duong, vat dung

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi chi sach - nang hang va dung cong dan ((than cao) or (thai cao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi chi sach - nang hang va dung cong dan ((than cao) OR (thai cao)).
• Adding a wildcard symbol may retrieve word variants: doi chi sach - nang hang va dung cong dan ((than cao) or (thai cao))*.