Perhaps you should try some spelling variations:
trinh cong » trinh dung
lcuoi viet » cuoi viec, cuoi vien, luoc viet
khao luan » khau luan, khai luan, khanh luan
cuoi viet » co viet, nuoc viet, cua viet
chao luan » phap luan, khau luan, pham luan
hoc viet » hoc hien
trinh co » trinh do, trinh hoa, trinh ky
co lcuoi » co loi, co nguoi, co nuoi
cong lan » cong luan, cong lang, cong san
cac cay » ca cay, cac cam, cac cap
cac bac » cac bai, cac ban, cac cach
cay co » cac co, tay co, cay cong
lan va » luan va, lanh va, lan van
bac co » bac cao, bac bo, cac co
co lan » cao lan, co ban, co dan

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 cong lan va cac cay co hoc viet nam ) or ( cong trinh co lan va cac bac co ((nguoi viet) or (cuoi viet)) nam ))) or ( cong trinh ((chao luan) OR (khao luan)) va cac cay co lcuoi viet nam ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( cong trinh cong lan va cac cay co hoc viet nam ) OR ( cong trinh co lan va cac bac co ((nguoi viet) OR (cuoi viet)) nam ))) OR ( cong trinh ((chao luan) OR (khao luan)) va cac cay co lcuoi viet nam ))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( cong trinh cong lan va cac cay co hoc viet nam ) or ( cong trinh co lan va cac bac co ((nguoi viet) or (cuoi viet)) nam ))) or ( cong trinh ((chao luan) OR (khao luan)) va cac cay co lcuoi viet nam ))*".