Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
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 » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua
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: toc sach ky ((mang xa) or (nang x)) hoi. hieu van lam thuc pham minh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((mang xa) OR (nang x)) hoi. hieu van lam thuc pham minh va cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((mang xa) or (nang x)) hoi. hieu van lam thuc pham minh va cua tre*.