Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
hieu van » hieu va, thien van, lieu va
lam thuc » lam thuoc, am thuc, nam thuc
sach ky » sac ky, sach y, sach ty
mang xa » lang xa, mang may, dang xay
van lam » van nam
minh va » tinh va, sinh va, sinh vat
cua tre » cuu tre, cua triet, dua tren
cua te » cua tu
pham » phan

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

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