Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » hieu va, thien van, lieu va
sach thu » sach thue, sach thieu, sach tham
cac duc » cac du, cao duc, cac dac
cua tre » cuu tre, cua triet, dua tren
duc ban » duc tan, duc van, dua ban
van cac » van hac, van cau, van bac
sach tu » cach tu, sach ty, sach uu
hang x » nang x, hoang xa, chang xu
cua te » cua tu
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 cac duc ban thanh dai ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach tu) OR (sach thu)) hang x hoi. hieu van cac duc ban thanh dai ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach tu) or (sach thu)) hang x hoi. hieu van cac duc ban thanh dai ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: te ((sach tu) or (sach thu)) hang x hoi. hieu van cac duc ban thanh dai ((cua tre) OR (cua te))*.