Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
lam duoc » nam duoc, luat duoc, lam thuoc
duoc ban » duc ban, quoc ban, buoc ban
ban hanh » ban hang
cua viet » ca viet, hoa viet, cua vat
tu sach » thu sach, su sach, te sach
tang xa » trang xa, tang ma, lang xa
van lam » van nam
cuu tre » cua tre, cau tren, cau treo
y tang » ky tang, 6 tang, 7 tang

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y tang xa hoi. hieu van lam duoc ban hanh vi ((cua viet) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y tang xa hoi. hieu van lam duoc ban hanh vi ((cua viet) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: tu sach y tang xa hoi. hieu van lam duoc ban hanh vi ((cua viet) or (cuu tre))*.