Perhaps you should try some spelling variations:
sach tham » sach nha
sach thu » sach thue, sach thieu, cach thuc
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
chua tre » chua tri, cua tre, chua trieu
xay hoi » xa hoi, tay hoi, cay phoi
thuc va » thuc vat, thuc dan, thuc day
va hang » van hang, va nang, va lang
va chua » vua chua, ca chua, va chu

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 thu) or (sach tham)) thong xay hoi. hieu van nam thuc va hang va chua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach thu) OR (sach tham)) thong xay hoi. hieu van nam thuc va hang va chua tre.
• Adding a wildcard symbol may retrieve word variants: te ((sach thu) or (sach tham)) thong xay hoi. hieu van nam thuc va hang va chua tre*.