Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cuu tre » cau tren, cau treo
va hanh » van hanh, va thanh, va danh
dan soc » dan toc, dan hoc, dan so
van dan » van ban, ban dan, van dao
cua tre » cua te, cua triet, dua tren
lang xa » lang ha, dang xay, lang van
sang ky » sang kyo, dang ky, tang ky
san ky » van ky, dan ky, ban ky
soc va » hoc va, loc va, doc va

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 (sang ky)) lang xa hoi. hieu van dan soc va hanh vi ((cuu tre) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((san ky) OR (sang ky)) lang xa hoi. hieu van dan soc va hanh vi ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((san ky) OR (sang ky)) lang xa hoi. hieu van dan soc va hanh vi ((cuu tre) or (cua tre))".
• Adding a wildcard symbol may retrieve word variants: te ((san ky) OR (sang ky)) lang xa hoi. hieu van dan soc va hanh vi ((cuu tre) or (cua tre))*.