Perhaps you should try some spelling variations:
cach dung » sach dung, cach mang, tac dung
ban thanh » ban hanh, ban hang
thanh hai » thanh phan, thanh hoa, thanh san
dung ban » dung san, dung dan, dong ban
hieu ve » hieu va, hieu van
ve cach » va cach, ve cac, ve canh
cua tre » cuu tre, cua triet, dua tren
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
nang o » nang co, nang ho, nang ro
cua te » cua tu
o hoi » co hoi, o hoc, o hai

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 nang o hoi. hieu ve cach dung ban thanh hai ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky nang o hoi. hieu ve cach dung ban thanh hai ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: tu sac ky nang o hoi. hieu ve cach dung ban thanh hai ((cua tre) or (cua te))*.