Perhaps you should try some spelling variations:
trien quang » tran quang, tuyen quang, dien quang
thong huong » thong thuong, thong duong, thong thong
hieu quang » thieu quang, hieu quan, hieu qua
hanh tranh » hanh trinh, hanh trang, lanh tranh
va thong » va thuong, va phuong, he thong
dan toan » van toan, dan than, manh toan
toan ban » van ban

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hieu quang) or (trien quang)) - ((hanh tranh) OR (canh tranh)) va thong huong dan toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hieu quang) OR (trien quang)) - ((hanh tranh) OR (canh tranh)) va thong huong dan toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((hieu quang) or (trien quang)) - ((hanh tranh) OR (canh tranh)) va thong huong dan toan ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((hieu quang) or (trien quang)) - ((hanh tranh) OR (canh tranh)) va thong huong dan toan ban*.