Perhaps you should try some spelling variations:
hieu ve » hieu va, hieu van
cac loc » cac lop, cac hoc, cac nuoc
cac toc » cac toi, cac nuoc, cac thoi
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
sac ky » sai ky
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: tu ((sac ky) or (cac ky)) nang x hoi. hieu ve ((cac loc) or (cac toc)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (cac ky)) nang x hoi. hieu ve ((cac loc) OR (cac toc)) va hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) or (cac ky)) nang x hoi. hieu ve ((cac loc) or (cac toc)) va hanh vi cua tre*.