Perhaps you should try some spelling variations:
ban thanh » ban hang
hieu van » hieu va, thien van, lieu va
ban hanh » ban hang
su sach » so sach, vu sach
van cuu » van cau, van chu, van cu
cuu tre » cua tre, cau tren, cau treo
sach ky » sac ky, sach y, sach ty
lam duc » lam duoc, nam duoc, lam dung
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang

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 ky lang xa hoi. hieu van ((lam duc) or (pham duc)) ((ban thanh) OR (ban hanh)) van cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky lang xa hoi. hieu van ((lam duc) OR (pham duc)) ((ban thanh) OR (ban hanh)) van cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky lang xa hoi. hieu van ((lam duc) or (pham duc)) ((ban thanh) OR (ban hanh)) van cuu tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky lang xa hoi. hieu van ((lam duc) or (pham duc)) ((ban thanh) OR (ban hanh)) van cuu tre*.