Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
ban thanh » ban hanh, ban hang
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
sach tu » cach tu, sach ty, sach uu
van cau » van dau, van hau, van chat
cau duc » cao duc, cau luc, chu duc
duc ban » duc tan, duc van, dua ban
cua tre » cua te, cuu tre, cua triet
hang x » nang x, hoang xa, chang xu
x hoi » xa hoi, o hoi, x ho

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 tu) or (sach thu)) hang x hoi. hieu van cau duc ban thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach tu) OR (sach thu)) hang x hoi. hieu van cau duc ban thanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: te ((sach tu) or (sach thu)) hang x hoi. hieu van cau duc ban thanh dai cua tre*.