Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cua viet » ca viet, cua vat, cua dieu
thanh vi » hanh vi, thanh va, thanh ve
va thanh » gia thanh, ban thanh, va tinh
thuc va » thuc vat, thuc dan, thuc day
su sach » vu sach
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
so sach » so sanh, bo sach, co sach
van am » van nam, van lam, van dam

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 thanh vi ((cua viet) OR (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 am thuc va thanh vi ((cua viet) OR (hoa viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) ky tang xa hoi. hieu van am thuc va thanh vi ((cua viet) OR (hoa viet))".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ky tang xa hoi. hieu van am thuc va thanh vi ((cua viet) OR (hoa viet))*.