Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam tu
hanh tai » thanh tai, hang tai, han tai
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
ky tang » ky nang, ky dang, kho tang
tang ma » mang may, tang van
xa hanh » xa thanh, xa khanh, va hanh
cua tre » cuu tre, cua triet, dua tren
ma hoi » mai hoi, xa hoi, ma hoa
cua te » cua tu

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 ky tang ma hoi. hieu van ((nam thuc) or (nam thu)) xa hanh tai ((cua tre) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky tang ma hoi. hieu van ((nam thuc) OR (nam thu)) xa hanh tai ((cua tre) OR (cua te)).
• Adding a wildcard symbol may retrieve word variants: su sach ky tang ma hoi. hieu van ((nam thuc) or (nam thu)) xa hanh tai ((cua tre) or (cua te))*.