Perhaps you should try some spelling variations:
trinh chuan » trinh han, trinh quan, trinh luan
chuan luan » chuyen luan, chuan doan, quan luan
dung dang » dung dan, dung dong, dung dung
dung danh » dung doanh, dung dan, cuong danh
hieu luat » hieu qua
hien soat » thien hoat, kiem soat, bien soan
van hieu » cao hieu
van hien » van tien

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( trinh ((dung dang) OR (dung danh)) van hieu luat ) OR ( trinh chuan luan van hien soat ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( trinh ((dung dang) OR (dung danh)) van hieu luat ) or ( trinh chuan luan van hien soat ))~".
• Adding a wildcard symbol may retrieve word variants: (( trinh ((dung dang) OR (dung danh)) van hieu luat ) or ( trinh chuan luan van hien soat ))*.