Perhaps you should try some spelling variations:
hien cong » thien cong, tien cong, dien cong
dung lang » dung dang, dung nang, dung land
lang van » dang van, tang van, hoang van
van hieu » cao hieu
hieu luc » hieu luat, hieu qua
lien qua » lien quan, vien quan, khien qua
quan van » luan van, quan va, quan luan
van hien » van tien
tin » tinh

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tin dung lang van hieu luc ) or ( lien qua quan van hien cong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tin dung lang van hieu luc ) OR ( lien qua quan van hien cong )).
• Adding a wildcard symbol may retrieve word variants: (( tin dung lang van hieu luc ) or ( lien qua quan van hien cong ))*.