Perhaps you should try some spelling variations:
trinh huong » trinh phuong, tinh huong, trinh duong
hoang duong » hoang vuong, hoang dung, hoang tuong
trinh hoang » trinh hoan, minh hoang, trinh han
trinh co » trinh do, trinh cong, trinh hoa
duong va » duong van, dung va, luong va
hoi viet » hai viet, thai viet, cuoi viet
mai viet » thi viet
co dang » cao dang, co dan, co dong
dang va » dang van, dang vat, hang va
bac cau » bach cau, ba cau, bac can
cua cau » chua cau, cua cac, cua chu
oi viet » o viet, cuoi viet, gioi viet
dan va » doan va, dan ca, ban va
ca cau » cac cau, can cau, ca cac
va bac » van bac, va cac, va bai

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 co dang va ((ca cau) OR (cua cau)) do ((oi viet) or (hoi viet)) nam ) or ((( cong trinh huong dan va bac cau do ((oi viet) or (hoi viet)) nam ) or ( cong trinh hoang duong va bac cau do ((m((oi viet) or (hoi viet))) or (mai viet)) nam ))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( cong trinh co dang va ((ca cau) OR (cua cau)) do ((oi viet) OR (hoi viet)) nam ) OR ((( cong trinh huong dan va bac cau do ((oi viet) OR (hoi viet)) nam ) OR ( cong trinh hoang duong va bac cau do ((m((oi viet) OR (hoi viet))) OR (mai viet)) nam )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( cong trinh co dang va ((ca cau) OR (cua cau)) do ((oi viet) or (hoi viet)) nam ) or ((( cong trinh huong dan va bac cau do ((oi viet) or (hoi viet)) nam ) or ( cong trinh hoang duong va bac cau do ((m((oi viet) or (hoi viet))) or (mai viet)) nam ))))".
• Adding a wildcard symbol may retrieve word variants: (( cong trinh co dang va ((ca cau) OR (cua cau)) do ((oi viet) or (hoi viet)) nam ) or ((( cong trinh huong dan va bac cau do ((oi viet) or (hoi viet)) nam ) or ( cong trinh hoang duong va bac cau do ((m((oi viet) or (hoi viet))) or (mai viet)) nam ))))*.