Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hac thuc » hoc thuc, ha thuc, thach thuc
vat hanh » vat thanh, van hanh, va hanh
cua viet » ca viet, hoa viet, cua vat
su sach » so sach, vu sach
co sach » bo sach, cuon sach, hoc sach
van hac » van hoc, van ha, van hai
y nang » ky nang, ly nang, v nang
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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: ((su sach) OR (co sach)) y nang x hoi. hieu van hac thuc vat hanh vi cua viet~.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (co sach)) y nang x hoi. hieu van hac thuc vat hanh vi cua viet*.