Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, tu cach
te sach » toc sach
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
duc ban » duc tan, dua ban, duc man
duc van » duc va, duc tan, duc manh
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua
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: ((tu sach) OR (te sach)) ky nang x hoi. hieu vu cham ((duc ban) OR (duc van)) hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) ky nang x hoi. hieu vu cham ((duc ban) OR (duc van)) hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ky nang x hoi. hieu vu cham ((duc ban) OR (duc van)) hanh vi cua tre*.