Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu van » thien van, lieu va, hieu ve
nam thuc » nam thuoc, am thuc, nam thu
hanh ca » hanh cac, hanh cat, hanh cua
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
nang co » nang cao, nang doc, nang noi
nang o » nang ho, nang ro, nang x
ca cua » co cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach y ((nang o) OR (nang co)) hai. ((hieu va) or (hieu van)) nam thuc va hanh ca cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach y ((nang o) OR (nang co)) hai. ((hieu va) OR (hieu van)) nam thuc va hanh ca cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach y ((nang o) OR (nang co)) hai. ((hieu va) or (hieu van)) nam thuc va hanh ca cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach y ((nang o) OR (nang co)) hai. ((hieu va) or (hieu van)) nam thuc va hanh ca cua tre*.