Perhaps you should try some spelling variations:
sach nang » cach mang, sach dung, sach danh
nang nang » nang sang, nang hang, chang nang
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
su sach » so sach, vu sach
cua tre » cuu tre, cua triet, dua tren
hanh de » hanh ve, hanh kem
hieu va » lieu va, hieu qua
hieu ve » hieu van
cua te » cua tu
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 nang nang x hoi. ((hieu ve) OR (hieu va)) cau truc van hanh de ((cua tre) OR (cua te))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach nang nang x hoi. ((hieu ve) OR (hieu va)) cau truc van hanh de ((cua tre) or (cua te))~".
• Adding a wildcard symbol may retrieve word variants: su sach nang nang x hoi. ((hieu ve) OR (hieu va)) cau truc van hanh de ((cua tre) or (cua te))*.