Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
thuc ban » thuoc ban, thuc dan, thu ban
thanh di » thanh doi, thanh de, thanh do
cua viet » ca viet, hoa viet, cua vat
su sach » vu sach
so sach » so sanh, bo sach, co sach
ky tang » ky dang, kho tang, ky trong
van am » van nam, van lam, van dam
di cua » dai cua, doi cua, de cua

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) OR (ky nang)) xa hoi. hieu van am thuc ban thanh di cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ((ky tang) OR (ky nang)) xa hoi. hieu van am thuc ban thanh di cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ((ky tang) OR (ky nang)) xa hoi. hieu van am thuc ban thanh di cua viet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ((ky tang) OR (ky nang)) xa hoi. hieu van am thuc ban thanh di cua viet*.