Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, te sach, tu cach
su sach » so sach, vu sach
van cac » van hac, van cau, van bac
cac dac » cac dan, cac dai, cac bac
dac ban » cac ban, dac san, duc ban
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: ((tu sach) OR (su sach)) y nang x ho. hieu van cac dac ban thanh dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (su sach)) y nang x ho. hieu van cac dac ban thanh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (su sach)) y nang x ho. hieu van cac dac ban thanh dai cua tre*.