Perhaps you should try some spelling variations:
ban thanh » ban hang
hieu hien » bieu hien, dieu hien, chieu chien
thu sach » tu sach, thuat sach, thuoc sach
ban hanh » ban hang
cau tren » cu tren, dau tren, ca tren
sach ky » sac ky, sach y, sach ty
dai duc » dao duc, dai dua, mai duc
vai cau » va cau, van cau, vai cac
x hoi » xa hoi, o hoi, 5 hoi

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 ky nang ((x hoi) or (x ho)). hieu hien dai duc ((ban thanh) or (ban hanh)) vai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang ((x hoi) OR (x ho)). hieu hien dai duc ((ban thanh) OR (ban hanh)) vai cau tren.
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang ((x hoi) or (x ho)). hieu hien dai duc ((ban thanh) or (ban hanh)) vai cau tren*.