Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
ban thanh » ban hanh, ban hang
thanh vi » hanh vi, thanh va, thanh ve
su sach » so sach, vu sach
hoa hoi » khoa hoi, hoa hoc, hoa doi
duc ban » duc tan, duc van, dua ban
cam duc » cam xuc, cao duc, pham duc
cua tre » cua te, cuu tre, cua triet
ky lang » ky nang, ky dang, ky tang
ha hoi » ha noi, xa hoi, va hoi
va cam » va cham, va cac, va cao
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (thuoc sach)) ky lang ((ha hoi) OR (hoa hoi)). lieu va cam duc ban thanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (thuoc sach)) ky lang ((ha hoi) OR (hoa hoi)). lieu va cam duc ban thanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (thuoc sach)) ky lang ((ha hoi) OR (hoa hoi)). lieu va cam duc ban thanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (thuoc sach)) ky lang ((ha hoi) OR (hoa hoi)). lieu va cam duc ban thanh vi cua tre*.