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

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 ((hcuoi viet) or (cuoi viet)) nam ))) or ( cong trinh chao 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 ((hcuoi viet) OR (cuoi viet)) nam ))) OR ( cong trinh chao luan va cac cay co lcuoi viet nam )).
• Adding a wildcard symbol may retrieve word variants: (((( cong trinh cong lan va cac cay co hoc viet nam ) or ( cong trinh co lan va cac bac co ((hcuoi viet) or (cuoi viet)) nam ))) or ( cong trinh chao luan va cac cay co lcuoi viet nam ))*.