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, trinh cau
cuoi viet » co viet, cua viet, gioi viet
nhan dang » nhan dan, phan dang, tran dang
khau luan » khoa luan, phap luan, pham luan
nuoc viet » ngoc viet, hoc viet, toc viet
cao luan » cao lan, cao quan, cao xuan
dang van » hoang van, hang va
dat viet » dao viet, dai viet, dan viet
cao cay » cao cap, cho cay, tao cay
da viet » dao viet, dai viet, dan viet
luan va » luan van, luat va
cac mau » cam mau, sach mau
hac cay » cac cay, hoc cay, tac cay
van hac » van hoc, van ha, van hai
cac cau » bac cau, ca cau, cac cam
co hoi » co hoc, co loi
cay co » cac co, tay co, cay cong
va cao » va cac, va co, va dao
co dan » co ban, ca dan, cao dang

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