Perhaps you should try some spelling variations:
hanh vai » hanh vi, hanh va, hanh tai
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
vai cua » dai cua, hai cua, lai cua
thu van » thuc van, thuy van, tu van
cac thu » cach thuc, cac thoi
hieu va » lieu va, hieu qua
dai hoi » dai hoc, dai hai, dai moi
mai hoi » mai khoi, lai hoi, mai doi
ky sang » ky dang, ky tang, duy sang
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 sang) or (ky nang)) ((mai hoi) OR (dai hoi)). hieu va cac thu van hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky sang) OR (ky nang)) ((mai hoi) OR (dai hoi)). hieu va cac thu van hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky sang) or (ky nang)) ((mai hoi) OR (dai hoi)). hieu va cac thu van hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky sang) or (ky nang)) ((mai hoi) OR (dai hoi)). hieu va cac thu van hanh vai cua tre*.