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
dot viet » dat viet, do viet, doc viet
hai viet » thai viet, mai viet, tai viet
dang van » hoang van, hang va
cao luan » cao lan, cao quan, cao xuan
co cuoi » co nuoi, cho cuoc, co nguoi
cac cay » ca cay, cac cam, cac cap
van cac » van hac, van cau, van bac
luan va » luan van, luat va
cac cau » bac cau, ca cau, cac cam
cua cau » chua cau, cua chu, cua cay
cac mau » cam mau, sach mau
va cua » va chua, via cua, ca cua
co hai » co dai, co hoi, o hai
cay co » tay co, cay cong
cac co » cac cong

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 (cua cau))) or (cac mau)) co hai viet nam ) or ((( cong trinh khau luan va cua cac co dot viet nam ) or ( cong trinh nhan dang van cac 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 (cua cau))) OR (cac mau)) co hai viet nam ) OR ((( cong trinh khau luan va cua cac co dot viet nam ) OR ( cong trinh nhan dang van cac cay co cuoi viet nam )))).
• Adding a wildcard symbol may retrieve word variants: (( cong trinh cao luan va ((((cac cau) or (cua cau))) or (cac mau)) co hai viet nam ) or ((( cong trinh khau luan va cua cac co dot viet nam ) or ( cong trinh nhan dang van cac cay co cuoi viet nam ))))*.