Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hieu ve » hieu va, hieu van
va hanh » va thanh, va danh, ban hanh
ve cham » va cham, ve chat, vu cham
cua tre » cua te, cuu tre, cua triet
mang xa » lang xa, mang may, dang xay
nang ma » tang ma, sang ma, nang cao
sac ky » cac ky, sai ky
vi cua » vai cua, di cua
tu sac » tu sach, tu cac, tu san

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 ((mang xa) or (nang ma)) hoi. hieu ve cham soc ((va hanh) or (van hanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((mang xa) OR (nang ma)) hoi. hieu ve cham soc ((va hanh) OR (van hanh)) vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((mang xa) or (nang ma)) hoi. hieu ve cham soc ((va hanh) or (van hanh)) vi cua tre*.