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

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

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