Perhaps you should try some spelling variations:
hanh tranh » canh tranh, hanh trinh, hanh trang
chieu sang » chieu sach, chieu xanh, nhieu tang
thong cong » trong cong, thong thong, phong chong
hieu lang » hieu quang, nhieu tang, hieu van
tranh cua » doanh cua, manh cua
tong cong » trong cong, cong cong, dung cong
tap toan » tap doan, tap quan, bai toan
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: ho ((chieu sang) OR (hieu lang)) - hanh tranh cua ((thong cong) OR (tong cong)) tap toan tap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu sang) or (hieu lang)) - hanh tranh cua ((thong cong) OR (tong cong)) tap toan tap~".
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sang) or (hieu lang)) - hanh tranh cua ((thong cong) OR (tong cong)) tap toan tap*.