Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
hien hanh » dieu hanh
trinh cuu » trinh cau, trinh cua, trinh chu
cong cong » cong dong, trong cong, dung cong
nang cong » nang song, dang cong, bang cong
doan cau » toan cau, doan dau, doan cap
toan tap » toan ban

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: hoc hien hanh - canh trinh cuu ((cong cong) OR (nang cong)) tap ((doan cau) OR (toan tap))~.
• Adding a wildcard symbol may retrieve word variants: hoc hien hanh - canh trinh cuu ((cong cong) or (nang cong)) tap ((doan cau) or (toan tap))*.