Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cua cach » cua cac, ca cach, cua bach
hieu cua » hieu qua, dieu cua, bieu cua
hai cua » thai cua, dai cua, hoi cua
anh hai » lanh hai, manh hai, anh thai
van anh » van thanh, tuan anh, van minh
cach tu » cach thuc
lang xa » lang ha, dang xay, lang van
mang xa » mang may, dang xay, mang cua
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) OR (lang xa)) hoi. hieu cua cach 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) OR (lang xa)) hoi. hieu cua cach tu van anh hai cua te~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ty ((mang xa) OR (lang xa)) hoi. hieu cua cach tu van anh hai cua te*.