Perhaps you should try some spelling variations:
trinh khai » trinh kham, trinh han, trinh tai
trinh khau » trinh kham, trinh khac, trinh han
trinh nhan » trinh han, trinh phan, trinh nha
nhan dang » nhan dan, phan dang, tran dang
trinh cao » trinh chao, trinh co, trinh cau
dat viet » dao viet, da viet, dai viet
hai viet » thai viet, mai viet, tai viet
dang van » hoang van, hang va
cao luan » cao lan, cao quan, cao xuan
cac mau » cam mau, sach mau
cac cay » cac cam, cac cap, tac cay
van cac » van hac, van cau, van bac
luan va » luan van, luat va
cac cau » bac cau, ca cau, cac cam
oi viet » hoi viet, o viet, cuoi viet
cay co » cac co, tay co, cay cong
co dat » coc dat, co dan, co dot
co hai » co dai, co hoi, o hai
ca cay » cua cay, ca cac, ca cao
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 luan va ((cac cau) or (cac mau)) co hai viet nam ) or ((( cong ((trinh khau) OR (trinh khai)) luan va ca cay co dat 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 luan va ((cac cau) OR (cac mau)) co hai viet nam ) OR ((( cong ((trinh khau) OR (trinh khai)) luan va ca cay co dat 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 luan va ((cac cau) or (cac mau)) co hai viet nam ) or ((( cong ((trinh khau) OR (trinh khai)) luan va ca cay co dat 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 luan va ((cac cau) or (cac mau)) co hai viet nam ) or ((( cong ((trinh khau) OR (trinh khai)) luan va ca cay co dat viet nam ) or ( cong trinh nhan dang van cac cay co oi viet nam ))))*.