Perhaps you should try some spelling variations:
chuong trinh » cong trinh
trinh cac » trinh cau, trinh chat, trinh chao
trinh can » trinh han, trinh san, trinh cau
cac ban » cac dan, cac van, cac bai
can ban » van ban, toan ban
so viet » hoc viet
cac cap » cao cap, cac cam, cac cau
cay co » tay co, cay cong
cac co » cac cong
o viet » hoc viet
cho so » cho son, co so, ho so

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (( chuong trinh cac ban va cac ((cay co) OR (cac co)) o viet nam ) OR ((( chuong trinh can ban va cac ((cay co) OR (cac co)) so viet nam ) OR ( chuong trinh cac ban va cac cap cho so viet nam ))))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( chuong trinh cac ban va cac ((cay co) OR (cac co)) o viet nam ) or ((( chuong trinh can ban va cac ((cay co) OR (cac co)) so viet nam ) or ( chuong trinh cac ban va cac cap cho so viet nam ))))~".
• Adding a wildcard symbol may retrieve word variants: (( chuong trinh cac ban va cac ((cay co) OR (cac co)) o viet nam ) or ((( chuong trinh can ban va cac ((cay co) OR (cac co)) so viet nam ) or ( chuong trinh cac ban va cac cap cho so viet nam ))))*.