Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
chieu sach » chinh sach, chiet tach, chieu sang
hieu manh » chieu xanh, hieu nganh, dieu hanh
trinh vat » trinh van, trinh luat, sinh vat
hang cong » hang nong, bang cong, thanh cong
dang cong » dung cong
van phan » van phong, van thanh, luan phan

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: ho ((hieu manh) OR (chieu sach)) - canh trinh vat ((hang cong) OR (dang cong)) van phan tu~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((hieu manh) or (chieu sach)) - canh trinh vat ((hang cong) OR (dang cong)) van phan tu~".
• Adding a wildcard symbol may retrieve word variants: ho ((hieu manh) or (chieu sach)) - canh trinh vat ((hang cong) OR (dang cong)) van phan tu*.