Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh va, hanh tai, hanh van
van cam » van nam, van lam, van cau
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
lai hoi » dai hoi, lai hoa, lai roi
mai hoi » mai khoi, dai hoi, mai doi
ky dang » ky nang, ky danh
cuu tre » cua tre, cau tren, cau treo
xuc va » duc va, tuc va, luc 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 ky dang ((mai hoi) OR (lai hoi)). hieu van cam xuc va ((hanh vai) or (hanh vi)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ((mai hoi) OR (lai hoi)). hieu van cam xuc va ((hanh vai) OR (hanh vi)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ((mai hoi) OR (lai hoi)). hieu van cam xuc va ((hanh vai) or (hanh vi)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ((mai hoi) OR (lai hoi)). hieu van cam xuc va ((hanh vai) or (hanh vi)) cuu tre*.