Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh va » thanh van, hanh va, thanh ha
sach thu » sach thue, sach thieu, sach tham
sach ty » sach y, sach tu, xach tay
duc ban » duc tan, duc van, dua ban
va cua » va chua, via cua, ca cua
ve cam » ve cham, ve cac, va cam
va cao » va cac, va co, va dao
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: su ((sach ty) OR (sach thu)) nang x hoi. hieu ((ve cam) or (va cao)) duc ban thanh va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach thu)) nang x hoi. hieu ((ve cam) OR (va cao)) duc ban thanh va cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach thu)) nang x hoi. hieu ((ve cam) or (va cao)) duc ban thanh va cua te".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) OR (sach thu)) nang x hoi. hieu ((ve cam) or (va cao)) duc ban thanh va cua te*.