Perhaps you should try some spelling variations:
voi nang » voi hang, hoi nang, voi rang
van nang » van quang, van ban, van dong
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
van lam » van nam
tuc va » thuc va, truc va, tuc xa
luc va » duc va, loc va
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.

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