Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
sach thu » sach thue, sach thieu, sach tham
thanh de » hanh de, thanh ve, thanh do
su sach » so sach, vu sach
cam duc » cam xuc, cao duc, nam duoc
cua tre » cua te, cuu tre, cua triet
cong ha » cong hoa, dong ha, cong tac
nang xa » nang x, lang xa, nang ma
de cua » le cua, te cua, dieu 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 thu ((nang xa) or (cong ha)) hoi. lieu va ((cam duc) OR (pham duc)) ban thanh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thu ((nang xa) OR (cong ha)) hoi. lieu va ((cam duc) OR (pham duc)) ban thanh de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thu ((nang xa) or (cong ha)) hoi. lieu va ((cam duc) OR (pham duc)) ban thanh de cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach thu ((nang xa) or (cong ha)) hoi. lieu va ((cam duc) OR (pham duc)) ban thanh de cua tre*.