Perhaps you should try some spelling variations:
trinh khau » trinh khai, trinh kham, trinh khac
trinh nhan » trinh han, trinh phan, trinh nha
nhan dang » nhan dan, phan dang, tran dang
khau luat » khau luan, thau luat, phap luat
hai viet » thai viet, mai viet, tai viet
dang van » hoang van, hang va
cao quan » co quan, bao quan, tac quan
hoi viet » oi viet, thai viet, cuoi viet
cao xuan » dao xuan, ngo xuan, vo xuan
luat va » xuat va, luat ve, suat va
cac mau » cam mau, sach mau
cac cau » bac cau, ca cau, cac cam
cac cay » ca cay, cac cam, cac cap
van cac » van hac, van cau, van bac
coc dat » hoc dat, chon dat, duoc dat
co hoi » co hoc, co loi
cay co » cac co, tay co, cay cong
co dan » co ban, ca dan, cao dang
co hai » co dai, o hai, so hai
ca cac » cua cac, va cac
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 quan) OR (cao xuan)) va ((cac cau) or (cac mau)) co hai viet nam ) or ((( cong trinh khau luat va ca cac ((coc dat) or (co dan)) viet nam ) or ( cong trinh nhan dang van cac cay co hoi viet nam ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( cong trinh ((cao quan) OR (cao xuan)) va ((cac cau) OR (cac mau)) co hai viet nam ) OR ((( cong trinh khau luat va ca cac ((coc dat) OR (co dan)) viet nam ) OR ( cong trinh nhan dang van cac cay co hoi viet nam )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( cong trinh ((cao quan) OR (cao xuan)) va ((cac cau) or (cac mau)) co hai viet nam ) or ((( cong trinh khau luat va ca cac ((coc dat) or (co dan)) viet nam ) or ( cong trinh nhan dang van cac cay co hoi viet nam ))))".
• Adding a wildcard symbol may retrieve word variants: (( cong trinh ((cao quan) OR (cao xuan)) va ((cac cau) or (cac mau)) co hai viet nam ) or ((( cong trinh khau luat va ca cac ((coc dat) or (co dan)) viet nam ) or ( cong trinh nhan dang van cac cay co hoi viet nam ))))*.