Perhaps you should try some spelling variations:
cua tre » cua te, cuu tre, cua triet
va hanh » van hanh, va thanh, va danh
cao duc » dao duc, cao suc, giao duc
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
sac ky » cac ky, sai ky
ve cao » va cao, ve bao, ve cac
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 ((nang xa) OR (nang ma)) hoi. hieu ve cao 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 ((nang xa) OR (nang ma)) hoi. hieu ve cao duc ((va hanh) OR (may tinh)) di cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((nang xa) OR (nang ma)) hoi. hieu ve cao duc ((va hanh) or (may tinh)) di cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((nang xa) OR (nang ma)) hoi. hieu ve cao duc ((va hanh) or (may tinh)) di cua tre*.