Perhaps you should try some spelling variations:
thanh do » thanh de, thanh pho, thanh hoa
hieu van » hieu va, thien van, lieu va
sach ty » sach thu, xach tay, sach hay
van cau » van dau, van hau, van chat
cua tre » cua te, cuu tre, cua triet
sach tu » sach thu, cach tu, sach uu
nang o » nang co, nang ho, nang ro
cau du » cau do, cac du, cau tu
du gia » duc gia, dau gia, vu gia
do cua » doi cua, co 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: thu ((((sach ty) or (sach y))) or (sach tu)) nang o hoi. hieu van cau du gia thanh do cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((((sach ty) OR (sach y))) OR (sach tu)) nang o hoi. hieu van cau du gia thanh do cua tre.
• Adding a wildcard symbol may retrieve word variants: thu ((((sach ty) or (sach y))) or (sach tu)) nang o hoi. hieu van cau du gia thanh do cua tre*.