Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
cua tre » cua te, cuu tre, cua triet
va hanh » va thanh, va danh, ban hanh
hai loc » hau loc, khai luoc, hai long
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
can ky » van ky, ban ky, tan ky
va hai » van hai, va chai, va khai
dan ky » van ky
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 va hai loc ((va hanh) OR (van hanh)) 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 va hai loc ((va hanh) OR (van hanh)) 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 va hai loc ((va hanh) OR (van hanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((can ky) or (dan ky)) lang xa hoi. hieu va hai loc ((va hanh) OR (van hanh)) vi cua tre*.