Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hanh lai » hanh lam, hanh tai, thanh lap
cua tre » cua te, cuu tre, dua tren
va hanh » van hanh, va thanh, va danh
cac loc » cac lop, cac toc, cac hoc
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
mang xa » lang xa, mang may, dang xay
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
loc va » hoc va, luc va
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 cac loc va hanh lai ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((mang xa) OR (nang ma)) hoi. hieu ve cac loc va hanh lai ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((mang xa) or (nang ma)) hoi. hieu ve cac loc va hanh lai ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((mang xa) or (nang ma)) hoi. hieu ve cac loc va hanh lai ((cua tre) OR (cua triet))*.