Perhaps you should try some spelling variations:
van cong » van dong, van phong, phan cong
cong cua » cong cu, dong cua, huong cua
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
hieu ve » hieu van
hieu va » lieu va, hieu qua
cac luc » cau luc, coc luc, cac nuoc
tu sai » tu bai, tu san, tu cai
sai ky » sac ky
luc va » duc va, tuc va, loc va
cua cu » cua chu, cua cau, cua su

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

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