Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
thanh hai » thanh phan, thanh hoa, thanh san
ban thanh » ban hanh, ban hang
lam duoc » nam duoc, luat duoc, lam thuoc
hieu van » hieu va, thien van, lieu va
duoc ban » duc ban, quoc ban, buoc ban
cua tre » cua te, cuu tre, dua tren
van lam » van nam
sach ky » sach y, sach ty, sach kem
sac ky » cac ky, sai ky
x hoi » xa hoi, o hoi, x ho

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

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