Perhaps you should try some spelling variations:
duong tam » duong tai, dong tam, duong lam
than bien » phan bien, tan bien, thanh vien
bien soan » bien so
hieu luat » hieu qua
tam than » ban than
anh nhan » danh nhan, doanh nhan, thanh nhan
nhan dan » phan dau, gian dan, nhan tai
van hieu » cao hieu
dan van » dang van, doan van, dao van

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( dinh duong tam than bien soan ) or ( anh nhan dan van hieu luat ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( dinh duong tam than bien soan ) OR ( anh nhan dan van hieu luat )).
• Adding a wildcard symbol may retrieve word variants: (( dinh duong tam than bien soan ) or ( anh nhan dan van hieu luat ))*.