Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu sang » chieu sang, hieu lang, hieu quang
va phuong » va thuong, cac phuong
doc hieu » toc thieu, hoc thieu, hoc hien
va thong » va thuong, he thong, va cong
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu sang - thanh trung ((va thong) OR (va phuong)) cong dan toan cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu sang - thanh trung ((va thong) OR (va phuong)) cong dan toan cao*".