Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
nam thuc » nam thuoc, nam thu, nam tu
cau tren » cu tren, dau tren, ca tren
lang ha » long ha
hieu va » lieu va, hieu qua
ky lang » ky nang, ky dang, ky tang
sach ky » sac ky, sach y, sach ty
dan vai » dan va, dan tai, dan vat
cuu tre » cua tre, cau treo
ha hoi » hoa hoi, ha noi, xa hoi
va dan » ca dan, va dao, va dau

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky lang ha hoi. hieu va ((nam thuc) OR (am thuc)) va dan vai ((cuu tre) OR (cau tren))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ky lang ha hoi. hieu va ((nam thuc) OR (am thuc)) va dan vai ((cuu tre) or (cau tren))~".
• Adding a wildcard symbol may retrieve word variants: doc sach ky lang ha hoi. hieu va ((nam thuc) OR (am thuc)) va dan vai ((cuu tre) or (cau tren))*.