Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
nam thuc » nam thuoc, am thuc, nam thu
tang van » dang van, hoang van, trong van
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, cam tu, dam thuc
so sach » bo sach, co sach, hoc sach
van hoi » van hoa, van hoc, van hoe
so sanh » do sanh
hieu ve » hieu va, hieu van
y tang » ky tang, 6 tang, 7 tang
vi cua » vai cua, di cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) y tang van hoi. hieu ve ((cam tuc) OR (nam thuc)) va hanh vi cua viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) OR (so sanh)) y tang van hoi. hieu ve ((cam tuc) or (nam thuc)) va hanh vi cua viet~".
• Adding a wildcard symbol may retrieve word variants: ((so sach) OR (so sanh)) y tang van hoi. hieu ve ((cam tuc) or (nam thuc)) va hanh vi cua viet*.