Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
ban hanh » ban hang
duoc ban » duc ban, quoc ban, buoc ban
hanh di » hanh vi, hanh de, hang di
van dau » van dao, phan dau
cua tre » cua te, cuu tre, cua triet
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
su sach » so sach, vu sach
di cua » dai cua, doi cua, de cua
van da » van dao, van dan, van dam

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuoc sach) or (su sach)) ky tang xa hoi. hieu ((van da) OR (van dau)) duoc ban hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (su sach)) ky tang xa hoi. hieu ((van da) OR (van dau)) duoc ban hanh di cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (su sach)) ky tang xa hoi. hieu ((van da) OR (van dau)) duoc ban hanh di cua tre*".