Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nam thuc » nam thuoc, am thuc, nam thu
cau treo » cau theo, cau tren, cau triet
van hoi » van hoa, van hoe, van loi
van hoc » van hoa
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
thuc va » thuc vat, thuc dan, thuc day
dan vai » dan va, dan vat, den vai
dan tai » van tai, dan thi, han tai
va nam » van nam, ha nam, va nay

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: toc sach ky lang ((van hoi) OR (van hoc)). hieu va nam thuc va ((dan vai) OR (dan tai)) cau treo~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky lang ((van hoi) OR (van hoc)). hieu va nam thuc va ((dan vai) or (dan tai)) cau treo~".
• Adding a wildcard symbol may retrieve word variants: toc sach ky lang ((van hoi) OR (van hoc)). hieu va nam thuc va ((dan vai) or (dan tai)) cau treo*.