Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
nam thuc » nam thuoc, am thuc, nam thu
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
cuu tre » cua tre, cau tren, cau treo
hieu va » hieu qua
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
dan va » dan ca, ban va, han va

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 dang xay hoi. ((hieu va) or (lieu va)) nam thuc va ((dan va) OR (doan va)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky dang xay hoi. ((hieu va) OR (lieu va)) nam thuc va ((dan va) OR (doan va)) cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky dang xay hoi. ((hieu va) or (lieu va)) nam thuc va ((dan va) OR (doan va)) cuu tre*".