Perhaps you should try some spelling variations:
trinh khau » trinh khai, trinh kham, trinh khac
trinh phan » trinh han, trinh quan, thanh phan
trinh cao » trinh chao, trinh co, trinh cau
phan dang » phan dau, phan cong, nhan dan
khau luan » khoa luan, phap luan, pham luan
cuoi viet » nguoi viet, co viet, nuoc viet
dang van » hoang van, hang va
hai viet » thai viet, mai viet, tai viet
cao luan » cao lan, cao quan, cao xuan
dot viet » dat viet, do viet, doc viet
cac cau » bac cau, ca cau, cac cam
co cuoi » co nuoi, cho cuoc, co nguoi
tac cay » tac can, tao cay, tac xay
cua cau » chua cau, cua cac, cua chu
cac cap » cao cap, cac cam, cac tap
cac cay » cac cam, cac cach, cac chat
cac mau » cam mau, sach mau
luan va » luan van, luat va
ca cay » cua cay, ca cac, ca cao
co hai » co dai, co hoi, o hai
cay co » cac co, tay co, cay cong
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 (cua cau))) or (cac mau)) co hai viet nam ) or ((( cong trinh khau luan va ca cay co dot viet nam ) or ( cong trinh phan dang van ((((cac cay) or (cac cap))) or (tac 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 ca cay co dot viet nam ) OR ( cong trinh phan dang van ((((cac cay) OR (cac cap))) OR (tac 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 ca cay co dot viet nam ) or ( cong trinh phan dang van ((((cac cay) or (cac cap))) or (tac cay)) co cuoi viet nam ))))*.