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

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 ca cay co ((dat viet) OR (da viet)) nam ) or ( cong trinh nhan dang van hac cay co cuoi 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 ca cay co ((dat viet) OR (da viet)) nam ) OR ( cong trinh nhan dang van hac cay co cuoi 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 ca cay co ((dat viet) OR (da viet)) nam ) or ( cong trinh nhan dang van hac cay co cuoi 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 ca cay co ((dat viet) OR (da viet)) nam ) or ( cong trinh nhan dang van hac cay co cuoi viet nam ))))*.