Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh li » thanh loi, thanh le, nhanh li
cau tren » cu tren, dau tren, ca tren
so sach » so sanh, bo sach, co sach
vu sach » vu bach, su sach, vu khach
hieu ve » hieu va, hieu van
cao duc » dao duc, cao suc, giao duc
duc ban » duc tan, duc van, dua ban
ve cao » va cao, ve bao, ve cac
li cau » loi cau, li ca, le cau
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: ((so sach) or (vu sach)) ky nang x hoi. hieu ve cao duc ban thanh li cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (vu sach)) ky nang x hoi. hieu ve cao duc ban thanh li cau tren.
• Adding a wildcard symbol may retrieve word variants: ((so sach) or (vu sach)) ky nang x hoi. hieu ve cao duc ban thanh li cau tren*.