Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
chieu sang » chieu sach, chieu xanh, nhieu tang
hieu lang » hieu quang, nhieu tang, hieu van
tranh cua » doanh cua, manh cua
hang dong » hang cong, hanh dong, lang dong
hang nong » thang long, han tong
toan ban » van 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: ho ((chieu sang) OR (hieu lang)) - hanh tranh cua ((hang dong) OR (hang nong)) tinh toan ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu sang) or (hieu lang)) - hanh tranh cua ((hang dong) OR (hang nong)) tinh toan ban~".
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sang) or (hieu lang)) - hanh tranh cua ((hang dong) OR (hang nong)) tinh toan ban*.