Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
thanh ca » thanh cha, thanh cac, thanh ha
va thanh » gia thanh, ban thanh, va tinh
lam duoc » nam duoc, luat duoc, lam thuoc
cua tre » cua te, cuu tre, dua tren
duoc va » nuoc va, duc va, duoc ma
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
van lam » van nam

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

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