Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
voi nang » voi hang, hoi nang, voi rang
thanh di » thanh doi, thanh de, thanh do
truc ban » thuc ban, truc dan, truc van
te sach » toc sach
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
vu nang » vuc nang, va nang, vu dang
va cau » van cau, va cac, va dau
di cua » dai cua, doi cua, de cua
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: te sach ((voi nang) or (vu nang)) ((o hoi) or (x ho)). hieu va cau truc ban thanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((voi nang) OR (vu nang)) ((o hoi) OR (x ho)). hieu va cau truc ban thanh di cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ((voi nang) or (vu nang)) ((o hoi) or (x ho)). hieu va cau truc ban thanh di cua tre*.