Perhaps you should try some spelling variations:
trinh khau » trinh khai, trinh kham, trinh khac
trinh nhan » trinh han, trinh phan, trinh nha
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
dot viet » dat viet, do viet, doc viet
hai viet » thai viet, mai viet, dai viet
tai viet » thi viet, mai viet, tai lieu
van bac » van ban, van bao, van hac
van cac » van hac, van cau, dan cac
oi viet » hoi viet, o viet, cuoi viet
cac cac » cac cach, ca cac, cac bac
luan va » luan van, luat va
ca cao » ca dao, cu cao, ca cac
cac co » cac cong
cay co » tay co, cay cong
ca cay » cua cay, cac cay, ca cac
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)) luan va cac cac co ((hai viet) or (tai viet)) nam ) or ((( cong trinh khau luan va ((ca cay) or (ca cao)) co dot viet nam ) or ( cong trinh nhan dang ((van cac) or (van bac)) cay co oi viet nam ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( cong ((trinh cao) OR (trinh cau)) luan va cac cac co ((hai viet) OR (tai viet)) nam ) OR ((( cong trinh khau luan va ((ca cay) OR (ca cao)) co dot viet nam ) OR ( cong trinh nhan dang ((van cac) OR (van bac)) cay co oi viet nam )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( cong ((trinh cao) OR (trinh cau)) luan va cac cac co ((hai viet) or (tai viet)) nam ) or ((( cong trinh khau luan va ((ca cay) or (ca cao)) co dot viet nam ) or ( cong trinh nhan dang ((van cac) or (van bac)) cay co oi viet nam ))))".
• Adding a wildcard symbol may retrieve word variants: (( cong ((trinh cao) OR (trinh cau)) luan va cac cac co ((hai viet) or (tai viet)) nam ) or ((( cong trinh khau luan va ((ca cay) or (ca cao)) co dot viet nam ) or ( cong trinh nhan dang ((van cac) or (van bac)) cay co oi viet nam ))))*.