Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
dang xay » dang van, van xay
hoc sach » hoc sinh, hoc cac, hoc anh
nam thuc » nam thuoc, am thuc, nam thu
thuc va » thuc vat, thuc dan, thuc day
hieu va » hieu qua
xay hoi » xa hoi, tay hoi, cay phoi
ky dang » ky nang, ky danh
cau tre » cau tren, cau treo, cau tra
va dan » ca dan, va dao, va dau
dan va » doan va, dan ca, ban va
va cau » van cau, va cac, va dau

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) or (hoc sach)) ky dang xay hoi. ((hieu va) or (lieu va)) nam thuc va dan va cau tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ky dang xay hoi. ((hieu va) OR (lieu va)) nam thuc va dan va cau tre.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) ky dang xay hoi. ((hieu va) or (lieu va)) nam thuc va dan va cau tre*.