Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
cac toc » cac toi, cac nuoc, cac thoi
cac tuc » cac tu, cac tac, cac nuoc
hieu va » lieu va
mang xa » lang xa, mang may, dang xay
ty mang » ty xang, ty hang, tin mang
vi cua » vai cua, di cua
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: toc sach ty mang xa hoi. ((hieu va) OR (hieu qua)) ((cac tuc) OR (cac toc)) van hanh vi cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty mang xa hoi. ((hieu va) or (hieu qua)) ((cac tuc) OR (cac toc)) van hanh vi cua te~".
• Adding a wildcard symbol may retrieve word variants: toc sach ty mang xa hoi. ((hieu va) or (hieu qua)) ((cac tuc) OR (cac toc)) van hanh vi cua te*.