Perhaps you should try some spelling variations:
hanh hai » thanh hai, nhanh hai, hang hai
ban hanh » ban hang
su sach » so sach, vu sach
cao duc » dao duc, cao suc, giao duc
hai cua » thai cua, dai cua, hoi cua
cam duc » cam xuc, pham duc, nam duoc
hieu ve » hieu va, hieu van
ky tang » ky dang, 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: su sach ((ky tang) or (ky nang)) xa hoi. hieu ve ((cam duc) or (cao duc)) ban hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky tang) OR (ky nang)) xa hoi. hieu ve ((cam duc) OR (cao duc)) ban hanh hai cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ((ky tang) or (ky nang)) xa hoi. hieu ve ((cam duc) or (cao duc)) ban hanh hai cua tre*.