Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu cua » hieu qua, bieu cua, hieu ca
dieu cua » dieu tra
van anh » van thanh, tuan anh, van minh
hai cua » thai cua, dai cua, hoi cua
ty mang » ty xang, ty hang, tin mang
mang xa » lang xa, mang may, dang xay
anh hai » lanh hai, manh hai, anh thai
bach tu » bach thu, cach tu, bac tu
tu van » tu va
cua te » cua tu

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: ((te sach) OR (toc sach)) ty mang xa hoi. ((hieu cua) OR (dieu cua)) bach tu van anh hai cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ty mang xa hoi. ((hieu cua) OR (dieu cua)) bach tu van anh hai cua te~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ty mang xa hoi. ((hieu cua) OR (dieu cua)) bach tu van anh hai cua te*.