Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sang ma » nang ma, sang tao, mang may
duc van » duc va, duc tan, duc manh
dao duc » giao duc, tao duoc
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
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 ((tang ma) or (sang ma)) hoa. hieu van dao duc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (thuoc sach)) ky ((tang ma) OR (sang ma)) hoa. hieu van dao duc van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (thuoc sach)) ky ((tang ma) or (sang ma)) hoa. hieu van dao duc van hanh vi cua tre*.