Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thanh vi » thanh va, thanh ve, nhanh vi
cau tren » cu tren, dau tren, ca tren
xang xa » lang xa, mang xa, ang xa
hieu va » hieu qua
cau luc » cau truc, cau phuc
y xang » ty xang
luc va » duc va, tuc va, loc va

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: thuoc sach y xang xa hoi. ((hieu va) OR (lieu va)) cau luc va ((thanh vi) OR (hanh vi)) cau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach y xang xa hoi. ((hieu va) OR (lieu va)) cau luc va ((thanh vi) or (hanh vi)) cau tren~".
• Adding a wildcard symbol may retrieve word variants: thuoc sach y xang xa hoi. ((hieu va) OR (lieu va)) cau luc va ((thanh vi) or (hanh vi)) cau tren*.