Perhaps you should try some spelling variations:
trinh khau » trinh khai, trinh kham, trinh khac
trinh nha » trinh phan, trinh chat, trinh chao
trinh cao » trinh chao, trinh co, trinh cau
khau luan » khoa luan, phap luan, pham luan
cao luan » cao lan, cao quan, cao xuan
dang van » hoang van, hang va
nha dang » nhan dang, nha hang, nha sang
hai viet » thai viet, mai viet, tai viet
cac cay » ca cay, cac cam, cac cap
van cac » van hac, van cau, van bac
oi viet » hoi viet, o viet, cuoi viet
cac cau » bac cau, ca cau, cac cam
cac mau » cam mau, sach mau
luan va » luan van, luat va
va cao » va cac, va co, va dao
co hai » co dai, co hoi, o hai
cay co » cac co, tay co, cay cong
co dat » coc dat, co dot, co dai
co dan » co ban, ca dan, cao dang
va ca » va cac, va cai, va cau
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 luan va ((cac cau) or (cac mau)) co hai viet nam ) or ((( cong trinh khau luan ((va ca) OR (va cao)) cay ((co dat) or (co dan)) viet nam ) or ( cong trinh nha dang van cac cay co oi 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 hai viet nam ) OR ((( cong trinh khau luan ((va ca) OR (va cao)) cay ((co dat) OR (co dan)) viet nam ) OR ( cong trinh nha dang van cac cay co oi 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 hai viet nam ) or ((( cong trinh khau luan ((va ca) OR (va cao)) cay ((co dat) or (co dan)) viet nam ) or ( cong trinh nha dang van cac cay co oi viet nam ))))".
• Adding a wildcard symbol may retrieve word variants: (( cong trinh cao luan va ((cac cau) or (cac mau)) co hai viet nam ) or ((( cong trinh khau luan ((va ca) OR (va cao)) cay ((co dat) or (co dan)) viet nam ) or ( cong trinh nha dang van cac cay co oi viet nam ))))*.