Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
vat tinh » sat tinh, vat sinh, hoat tinh
te sach » toc sach
sach ky » sac ky, sach y, sach ty
nang ha » nang hai, nang han, nang hoa
tinh va » tich va, trinh van, trinh vat
cua tre » cua te, cuu tre, dua tren

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang ha noi. hieu van nam thuc vat tinh va ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang ha noi. hieu van nam thuc vat tinh va ((cua tre) OR (cua triet)).
• Adding a wildcard symbol may retrieve word variants: te sach ky nang ha noi. hieu van nam thuc vat tinh va ((cua tre) or (cua triet))*.