Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
lang van » dang van, tang van, hoang van
coc ban » co ban, cac ban, hoc ban
loc ban » lo ban, hoc ban, hoc bang
bach ky » bac ky
lang xa » lang ha, dang xay
qua cao » qua cac, qua ca, qua cai
vi cau » va cau, ve cau, di cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu bach ky ((lang xa) OR (lang van)) hoi. hieu qua cao ((loc ban) or (coc ban)) hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu bach ky ((lang xa) OR (lang van)) hoi. hieu qua cao ((loc ban) OR (coc ban)) hanh vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu bach ky ((lang xa) OR (lang van)) hoi. hieu qua cao ((loc ban) or (coc ban)) hanh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: vu bach ky ((lang xa) OR (lang van)) hoi. hieu qua cao ((loc ban) or (coc ban)) hanh vi cau tren*.