Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
so sach » so sanh, bo sach, co sach
sach ky » sac ky, sach y, sach ty
ky lang » ky nang, ky dang, ky tang
lang ha » long ha
van cam » van nam, van lam, van cau
cua tre » cua te, cuu tre, cua triet
ha hoi » hoa hoi, ha noi, xa hoi
xac va » tac va, ac va, bac va
tuc va » thuc va, truc va, tuc xa
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 ky lang ha hoi. hieu van cam ((xac va) or (tuc va)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky lang ha hoi. hieu van cam ((xac va) OR (tuc va)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: so sach ky lang ha hoi. hieu van cam ((xac va) or (tuc va)) hanh vi cua tre*.