Perhaps you should try some spelling variations:
ban thanh » ban hanh
hieu van » hieu va, thien van, lieu va
lam thuc » lam thuoc, am thuc, nam thuc
ban hang » ngan hang
su sach » vu sach
van lam » van nam
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
so sach » so sanh, bo sach, co sach
vi hoa » voi hoa, vi hoc, va hoa

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) or (so sach)) ky tang xa hoi. hieu van lam thuc ((ban thanh) or (ban hang)) vi hoa viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ky tang xa hoi. hieu van lam thuc ((ban thanh) OR (ban hang)) vi hoa viet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky tang xa hoi. hieu van lam thuc ((ban thanh) or (ban hang)) vi hoa viet*.