Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
hieu va » lieu va, hieu qua
va hanh » va thanh, va danh, ban hanh
cac luc » cau luc, coc luc, cac nuoc
cua tre » cua te, cuu tre, cua triet
lang ha » long ha
ha hoi » hoa hoi, ha noi, xa hoi
sac ky » cac ky

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sai ky) or (sac ky)) lang ha hoi. hieu va cac luc ((va hanh) or (van hanh)) tri cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sai ky) OR (sac ky)) lang ha hoi. hieu va cac luc ((va hanh) OR (van hanh)) tri cua tre.
• Adding a wildcard symbol may retrieve word variants: te ((sai ky) or (sac ky)) lang ha hoi. hieu va cac luc ((va hanh) or (van hanh)) tri cua tre*.