Perhaps you should try some spelling variations:
sach thu » sach thue, sach tham, cach thuc
hieu van » hieu va, thien van, lieu va
va hanh » van hanh, va thanh, va danh
cau xuc » cam xuc, cau luc, cau truc
van cau » van dau, van hau, van chat
mang xa » lang xa, mang may, dang xay
cua tre » cua te, cuu tre, cua triet
ang xa » lang xa, dang xay, hoang xa
xuc va » duc va, tuc va, luc 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: su ((sach thu) OR (sach thieu)) ((ang xa) or (mang xa)) hoi. hieu van cau xuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach thu) OR (sach thieu)) ((ang xa) OR (mang xa)) hoi. hieu van cau xuc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach thu) OR (sach thieu)) ((ang xa) or (mang xa)) hoi. hieu van cau xuc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su ((sach thu) OR (sach thieu)) ((ang xa) or (mang xa)) hoi. hieu van cau xuc va hanh vi cua tre*.