Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
duc van » duc va, duc tan, duc manh
hanh de » hanh ve, hanh kem
cua tre » cua te, cuu tre, cua triet
qua ca » qua cac, qua cua, qua cai
ca duc » cao duc, cua duc, ca dua
de cua » le cua, te cua, dieu 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 (toc sach)) ky nang x hoi. hieu qua ca duc van hanh de cua tre~.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) ky nang x hoi. hieu qua ca duc van hanh de cua tre*.