Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
sach ky » sach y, sach ty, sach kem
sach tu » sach thu, cach tu, sach ty
van cau » van dau, van hau, van chat
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
cau tu » dau tu, cau truc
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 ky) OR (sac ky))) OR (sach tu)) nang x hoi. hieu van cau tu va hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((((sach ky) OR (sac ky))) or (sach tu)) nang x hoi. hieu van cau tu va hanh vi cua tre~".
• Adding a wildcard symbol may retrieve word variants: su ((((sach ky) OR (sac ky))) or (sach tu)) nang x hoi. hieu van cau tu va hanh vi cua tre*.