Perhaps you should try some spelling variations:
trinh cay » trinh cau, trinh may, trinh cac
soi viet » so viet, hoi viet, oi viet
hoc viet » hoc hien
cay ban » can ban, cac ban, tay ban
cac cau » cac mau, bac cau, ca cau
cac cap » cao cap, cac cam, cac cay
cau co » cau do, cac co, cay co
co soi » cot soi, co so, co hoi
do soi » do moi, do son, do voi
do sai » do dai, do hai, do mai

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: (((( cong trinh cay ban va cac cau co soi viet nam ) OR ( cong trinh cay ban va cac cau co hoc viet nam ))) OR ( cong trinh cay ban va cac cap ((do soi) OR (do sai)) viet nam ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((( cong trinh cay ban va cac cau co soi viet nam ) or ( cong trinh cay ban va cac cau co hoc viet nam ))) or ( cong trinh cay ban va cac cap ((do soi) OR (do sai)) viet nam ))~".
• Adding a wildcard symbol may retrieve word variants: (((( cong trinh cay ban va cac cau co soi viet nam ) or ( cong trinh cay ban va cac cau co hoc viet nam ))) or ( cong trinh cay ban va cac cap ((do soi) OR (do sai)) viet nam ))*.