Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hanh lam » thanh lap, hanh kem, hanh va
cham duc » pham duc, cham soc, pham duy
vu cham » va cham, vu kham, tu cham
cua tre » cua te, cuu tre, dua tren
va hanh » van hanh, va thanh, va danh
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
tang ma » tang van
hieu vu » hieu va, hieu ve, hieu su

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty ((tang ma) or (mang may)) hoi. hieu vu cham duc va hanh lam ((cua tre) OR (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty ((tang ma) OR (mang may)) hoi. hieu vu cham duc va hanh lam ((cua tre) OR (cua triet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty ((tang ma) or (mang may)) hoi. hieu vu cham duc va hanh lam ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: su sach ty ((tang ma) or (mang may)) hoi. hieu vu cham duc va hanh lam ((cua tre) OR (cua triet))*.