Perhaps you should try some spelling variations:
trinh khau » trinh khai, trinh kham, trinh khac
trinh nhan » trinh han, trinh phan, trinh nha
khau luan » khoa luan, phap luan, pham luan
nhan dang » nhan dan, phan dang, tran dang
trinh cao » trinh chao, trinh co, trinh cau
hai viet » thai viet, mai viet, tai viet
hoi viet » thai viet, cuoi viet, gioi viet
cao luan » cao lan, cao quan, cao xuan
oi viet » o viet, cuoi viet, gioi viet
co hai » co dai, o hai, so hai
va cau » van cau, va cac, va dau
cay co » cac co, tay co, cay cong
co hoi » co hoc, co loi
cau co » cau do, cac co, dau co
va ca » va cac, va cao, va cai
c cau » co cau, cu cau, ca cau
c cay » ca cay, _ cay, c can
co oi » co loi, co doi, co toi

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( cong trinh cao luan ((va ca) OR (va cau))c cau co hai viet nam ) or ((( cong trinh khau luan ((va ca) OR (va cau)) cay co hoi viet nam ) or ( cong trinh nhan dang ((va ca) OR (va cau))c cay co oi viet nam ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( cong trinh cao luan ((va ca) OR (va cau))c cau co hai viet nam ) OR ((( cong trinh khau luan ((va ca) OR (va cau)) cay co hoi viet nam ) OR ( cong trinh nhan dang ((va ca) OR (va cau))c cay co oi viet nam )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( cong trinh cao luan ((va ca) OR (va cau))c cau co hai viet nam ) or ((( cong trinh khau luan ((va ca) OR (va cau)) cay co hoi viet nam ) or ( cong trinh nhan dang ((va ca) OR (va cau))c cay co oi viet nam ))))".
• Adding a wildcard symbol may retrieve word variants: (( cong trinh cao luan ((va ca) OR (va cau))c cau co hai viet nam ) or ((( cong trinh khau luan ((va ca) OR (va cau)) cay co hoi viet nam ) or ( cong trinh nhan dang ((va ca) OR (va cau))c cay co oi viet nam ))))*.