Perhaps you should try some spelling variations:
trinh nhan » trinh han, trinh phan, trinh nha
trinh khau » trinh khai, trinh kham, trinh khac
trinh cao » trinh chao, trinh co, tinh cao
trinh cau » trinh chat, trinh chao, trinh tu
nhan dang » nhan dan, phan dang, tran dang
khau luan » khoa luan, phap luan, pham luan
hai viet » thai viet, mai viet, tai viet
dang van » hoang van, hang va
cac cay » ca cay, cac cam, cac cap
van cac » van hac, van cau, van bac
luan va » luan van, luat va
oi viet » hoi viet, o viet, cuoi viet
cac mau » cam mau, sach mau
quan ha » quan he
cac cau » bac cau, ca cau, cac cam
cay co » cac co, tay co, cay cong
co hai » co dai, co hoi, o hai
co dat » coc dat, co dot, co dai
ca cac » cua cac, va cac
co dan » co ban, ca dan, cao dang
va ca » va cac, va cao, va cai
co oi » co hoi, co loi, co doi

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