Perhaps you should try some spelling variations:
phuong cong » phuong dong, phong cong, phung cong
thieu sang » chieu sang, thieu khang, thieu quang
hanh tranh » hanh trinh, hanh trang, lanh tranh
hoc thieu » toc thieu, hoc hien
va phuong » va thuong, cac phuong
van toan » van tan, van thanh, manh toan
van tuan » van quan, van ban, anh tuan

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

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