Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
dang hai » dang khai, hang hai, dung hai
quoc ban » quoc bao, quoc lan, quoc quan
ban hanh » ban hang
ky dang » ky nang, ky danh
hai hoi » dai hoi, hai moi, hai hai
va chat » van chat, va phat, hoa chat
tu sac » tu sach, tu cac, tu san
cua tu » cua tuc, cua su, cua cu
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky dang hai hoi. hieu ((va chat) OR (cao chat)) quoc ban hanh tai ((cua te) or (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky dang hai hoi. hieu ((va chat) OR (cao chat)) quoc ban hanh tai ((cua te) OR (cua tu)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky dang hai hoi. hieu ((va chat) OR (cao chat)) quoc ban hanh tai ((cua te) or (cua tu))".
• Adding a wildcard symbol may retrieve word variants: tu sac ky dang hai hoi. hieu ((va chat) OR (cao chat)) quoc ban hanh tai ((cua te) or (cua tu))*.