Perhaps you should try some spelling variations:
su sach » so sach, vu sach
tu nong » tu dong, tu tong, tu tuong
tu cong » thu cong, te cong, tai cong
cac duc » cac du, cao duc, cac dac
va tinh » may tinh
va hanh » van hanh, va thanh, va danh
va cua » va chua, via cua, ca cua
cua tu » cua tuc, cua su, cua cu
x hoi » xa hoi, o hoi, x ho

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: su sach ((tu nong) OR (tu cong)) x hoi. lieu va cac duc ((va tinh) OR (va hanh)) va cua tu~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((tu nong) OR (tu cong)) x hoi. lieu va cac duc ((va tinh) or (va hanh)) va cua tu~".
• Adding a wildcard symbol may retrieve word variants: su sach ((tu nong) OR (tu cong)) x hoi. lieu va cac duc ((va tinh) or (va hanh)) va cua tu*.