Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
hanh vai » hanh vi, hanh va, hanh tai
cua viet » ca viet, hoa viet, cua vat
so sach » so sanh, bo sach, co sach
nang ma » tang ma, sang ma, nang cao
van cam » van nam, van lam, van cau
vai cua » dai cua, hai cua, lai cua
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
tuc va » thuc va, truc va, duc va

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y nang ma hoi. hieu van cam ((tuc va) or (tuc xa)) hanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y nang ma hoi. hieu van cam ((tuc va) OR (tuc xa)) hanh vai cua viet.
• Adding a wildcard symbol may retrieve word variants: so sach y nang ma hoi. hieu van cam ((tuc va) or (tuc xa)) hanh vai cua viet*.