Perhaps you should try some spelling variations:
ban thanh » ban hanh
hieu van » hieu va, thien van, lieu va
ban hang » ngan hang
su sach » vu sach
so sach » so sanh, bo sach, co sach
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
van am » van nam, van lam, van dam
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 dang xa hoi. hieu van am 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 dang xa hoi. hieu van am thuc ((ban thanh) OR (ban hang)) vi hoa viet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky dang xa hoi. hieu van am thuc ((ban thanh) or (ban hang)) vi hoa viet*.