Perhaps you should try some spelling variations:
dang xay » dang van, van xay
van hanh » van thanh, ban hanh, van anh
nang xa » nang x, lang xa, nang ma
hieu le » hieu ve, hieu he, hieu ly
va hanh » va thanh, va danh, ban hanh
cua tre » cua te, cuu tre, cua triet
tu sac » tu sach, tu cac, tu san
sac ky » cac ky, sai ky
le am » le ham, le nam, le a

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 xa) or (dang xay)) hoi. hieu le am thuc ((va hanh) or (van hanh)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((nang xa) OR (dang xay)) hoi. hieu le am thuc ((va hanh) OR (van hanh)) dai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((nang xa) or (dang xay)) hoi. hieu le am thuc ((va hanh) or (van hanh)) dai cua tre*.