Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cua viet » ca viet, hoa viet, cua vat
su sach » vu sach
so sach » so sanh, bo sach, co sach
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
van am » van nam, van lam, van dam
vi cua » vai cua, di 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 xa hoi. hieu van am thuc va hanh vi cua 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 am thuc va hanh vi cua viet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky tang xa hoi. hieu van am thuc va hanh vi cua viet*.