Perhaps you should try some spelling variations:
thanh hoa » thanh pho
ban thanh » ban hanh, ban hang
cham duc » cham soc, pham duy, phan duc
so sach » so sanh, bo sach, co sach
hoa cua » hoa chat, hoa xuat
hieu ve » hieu va, hieu van
ky dang » ky nang, ky danh
ky tang » ky nang, kho tang, ky trong
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ((ky tang) OR (ky dang)) xa hoi. hieu ve ((cham duc) or (pham duc)) ban thanh hoa cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((ky tang) OR (ky dang)) xa hoi. hieu ve ((cham duc) OR (pham duc)) ban thanh hoa cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((ky tang) OR (ky dang)) xa hoi. hieu ve ((cham duc) or (pham duc)) ban thanh hoa cua tre".
• Adding a wildcard symbol may retrieve word variants: so sach ((ky tang) OR (ky dang)) xa hoi. hieu ve ((cham duc) or (pham duc)) ban thanh hoa cua tre*.