Perhaps you should try some spelling variations:
hieu quan » hieu qua, lieu quan, thien quan
tranh va » tranh van, trang va, trinh va
cong dan » cong san, huong dan, cong dong
cong tan » cong tac, cong san, cong thanh
toan tai » doanh tai, toan ban, toan cao
toan tap » toan ban
ho hieu » ho chieu, hoi hieu, nho hieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho hieu quan - canh tranh va nhung ((cong dan) OR (cong tan)) ((toan tai) or (toan tap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu quan - canh tranh va nhung ((cong dan) OR (cong tan)) ((toan tai) OR (toan tap)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu quan - canh tranh va nhung ((cong dan) OR (cong tan)) ((toan tai) or (toan tap))".
• Adding a wildcard symbol may retrieve word variants: ho hieu quan - canh tranh va nhung ((cong dan) OR (cong tan)) ((toan tai) or (toan tap))*.