Perhaps you should try some spelling variations:
thanh vi » hanh vi, thanh va, thanh ve
hieu van » hieu va, thien van, lieu va
cua tre » cua te, cuu tre, cua triet
van cac » van hac, van cau, van bac
lang xa » lang ha, dang xay, lang van
can ky » van ky, ban ky, tan ky
dan ky » van ky
loc va » luc va
vi cua » vai cua, di cua

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

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