Perhaps you should try some spelling variations:
dan thuc » dan toc, am thuc
su sach » vu sach
so sach » so sanh, bo sach, co sach
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
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: ((su sach) OR (so sach)) y nang x hoi. hieu ve ((dan thuc) or (cam xuc)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) y nang x hoi. hieu ve ((dan thuc) OR (cam xuc)) va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) OR (so sach)) y nang x hoi. hieu ve ((dan thuc) or (cam xuc)) va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) OR (so sach)) y nang x hoi. hieu ve ((dan thuc) or (cam xuc)) va hanh vi cua tre*.