Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh ban » thanh san, thanh van, thanh bac
nang mai » nang ma, nang tai, lang mai
so sach » so sanh, bo sach, co sach
cao duc » dao duc, cao suc, tao duoc
ban cua » ban quan
mai hoi » mai khoi, dai hoi, lai hoi
hieu va » lieu va
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang

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 y nang mai hoi. ((hieu va) or (hieu qua)) ((cao duc) or (giao duc)) ban thanh ban cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y nang mai hoi. ((hieu va) OR (hieu qua)) ((cao duc) OR (giao duc)) ban thanh ban cua tre.
• Adding a wildcard symbol may retrieve word variants: so sach y nang mai hoi. ((hieu va) or (hieu qua)) ((cao duc) or (giao duc)) ban thanh ban cua tre*.