Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh hoa » thanh pho
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
cac dac » cac dan, cac dai, cac bac
dac ban » cac ban, dac san, duc ban
hoa cua » hoa chat, hoa xuat
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, x ho, 5 hoi
o hoi » co hoi, o hoc, o hai

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 (thu sach)) y nang ((x hoi) OR (o hoi)). lieu va cac dac ban thanh hoa cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) y nang ((x hoi) OR (o hoi)). lieu va cac dac ban thanh hoa cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) y nang ((x hoi) OR (o hoi)). lieu va cac dac ban thanh hoa cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) y nang ((x hoi) OR (o hoi)). lieu va cac dac ban thanh hoa cua tre*.