Perhaps you should try some spelling variations:
cac thoi » cac toi, cac hop, cac tro
su sach » so sach, vu sach
so sanh » do sanh
cac toc » cac toi, cac nuoc
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
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 sanh)) cam nang x hoi. hieu qua ((cac toc) OR (cac thoi)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sanh)) cam nang x hoi. hieu qua ((cac toc) OR (cac thoi)) va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sanh)) cam nang x hoi. hieu qua ((cac toc) OR (cac thoi)) va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sanh)) cam nang x hoi. hieu qua ((cac toc) OR (cac thoi)) va hanh vi cua tre*.