Perhaps you should try some spelling variations:
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
ve giao » te giao, viet giao, van giao
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
mang xa » lang xa, mang may, dang xay
sac ky » cac ky, sai ky
di cua » dai cua, doi cua, de 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 giao duc ((va hanh) or (may tinh)) di 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 giao duc ((va hanh) OR (may tinh)) di cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((mang xa) or (nang ma)) hoi. hieu ve giao duc ((va hanh) or (may tinh)) di cua tre*.