Perhaps you should try some spelling variations:
thanh duoc » hanh duoc, tranh duoc, thanh phuoc
ban thanh » ban hanh, ban hang
va thanh » gia thanh, va tinh
hieu ban » hieu van, dieu ban, lieu ban
su sach » so sach, vu sach
sach tu » sach thu, cach tu, sach ty
tu nang » tru nang, tu nong, tu nano
cua tre » cua te, cuu tre, cua triet
ve cua » le cua, de cua, te cua
x hoi » o 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: su sach tu nang ((x hoi) or (xa hoi)). hieu ban thanh duoc ((va thanh) OR (le thanh)) ve cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tu nang ((x hoi) OR (xa hoi)). hieu ban thanh duoc ((va thanh) OR (le thanh)) ve cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach tu nang ((x hoi) or (xa hoi)). hieu ban thanh duoc ((va thanh) OR (le thanh)) ve cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach tu nang ((x hoi) or (xa hoi)). hieu ban thanh duoc ((va thanh) OR (le thanh)) ve cua tre*.