Perhaps you should try some spelling variations:
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
va dinh » van dinh, va kinh, va tinh
cua tre » cua te, cuu tre, cua triet
san ky » sang ky, dan ky, ban ky
va cam » va cham, va cac, va cao
cam tu » cam thu, nam tu, dam tu
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: te ((san ky) OR (van ky)) nang x hoi. hieu va cam tu ((va hanh) or (va dinh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((san ky) OR (van ky)) nang x hoi. hieu va cam tu ((va hanh) OR (va dinh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((san ky) OR (van ky)) nang x hoi. hieu va cam tu ((va hanh) or (va dinh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((san ky) OR (van ky)) nang x hoi. hieu va cam tu ((va hanh) or (va dinh)) vi cua tre*.