Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
van nang » van quang, van ban, van dong
hang doi » hang loi, huong doi, hang tai
hang di » hang vi, hang dien, hang dich
bao luc » bao thuc
qua bao » qua ban, qua bau, qua lao
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va

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) OR (doc sach)) van nang xa hoi. hieu qua bao luc va ((hang di) OR (hang doi)) cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) van nang xa hoi. hieu qua bao luc va ((hang di) OR (hang doi)) cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) van nang xa hoi. hieu qua bao luc va ((hang di) OR (hang doi)) cua tre*.