Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh luc » thanh luu, than luc, nhan luc
hanh vai » hanh vi, hanh va, hanh tai
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, te sach, tu cach
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
nang ma » tang ma, sang ma, mang may
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) OR (su sach)) v ((nang ma) or (nang cao)) hoi. hieu van thanh luc va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) v ((nang ma) OR (nang cao)) hoi. hieu van thanh luc va hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) v ((nang ma) or (nang cao)) hoi. hieu van thanh luc va hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) v ((nang ma) or (nang cao)) hoi. hieu van thanh luc va hanh vai cua tre*.