Perhaps you should try some spelling variations:
lang van » dang van, tang van, hoang van
lang xa » lang ha, dang xay
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
va dam » van dam, va dao, va dau
dam tu » nam tu, cam tu, tam tu
thiet » thieu

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

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