Perhaps you should try some spelling variations:
thanh hoi » thanh hoai, thanh hoa, thanh hai
ban thanh » ban hanh, ban hang
thu sach » thuat sach, thuoc sach, thu hoach
cach dua » cach cua, cach dung, cac du
hieu ve » hieu va, hieu van
hoi cua » hoi chuc
dua ban » dia ban, cua ban, qua ban
ve cach » va cach, ve cac, ve canh
tu sach » su sach, te sach, tu cach
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 hoi

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)). hieu ve cach dua ban thanh hoi 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)). hieu ve cach dua ban thanh hoi 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)). hieu ve cach dua ban thanh hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) y nang ((x hoi) or (o hoi)). hieu ve cach dua ban thanh hoi cua tre*.