Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
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
truc va » thuc va, thuc vat, trung va
y nang » ky nang, ly nang, v nang
tuc va » thuc va, tuc xa, duc va
vi cua » vai cua, di cua

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 hoa. hieu van cam ((tuc va) or (truc va)) hanh vi cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y nang ma hoa. hieu van cam ((tuc va) OR (truc va)) hanh vi cua viet.
• Adding a wildcard symbol may retrieve word variants: so sach y nang ma hoa. hieu van cam ((tuc va) or (truc va)) hanh vi cua viet*.