Perhaps you should try some spelling variations:
phuong cong » phuong dong, phong cong, phung cong
hieu nganh » vien nganh, hiem ngan, hieu manh
thanh dung » thanh duong, thanh tung, thanh hung
hien hanh » dieu hanh
va phuong » va thuong, cac phuong
dan toan » van toan, manh toan, xuan toan
dan than » dan chan, ban than, van than

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: doc ((hien hanh) OR (hieu nganh)) - thanh dung va phuong cong ((dan toan) OR (dan than)) cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hien hanh) or (hieu nganh)) - thanh dung va phuong cong ((dan toan) OR (dan than)) cao~".
• Adding a wildcard symbol may retrieve word variants: doc ((hien hanh) or (hieu nganh)) - thanh dung va phuong cong ((dan toan) OR (dan than)) cao*.