Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sach » chinh sach, chiet tach, chieu sang
hieu quang » thieu quang, hieu quan, hieu qua
nhung cong » dung cong, thong cong, hang cong
trung cua » truong cua, trung tuan, trung cap
cua nhung » va nhung
san toan » van toan, manh toan, xuan toan
dan toan » van toan, dan than, manh toan

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho ((chieu sach) or (hieu quang)) - thanh trung cua nhung cong ((san toan) OR (dan toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chieu sach) OR (hieu quang)) - thanh trung cua nhung cong ((san toan) OR (dan toan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu sach) or (hieu quang)) - thanh trung cua nhung cong ((san toan) OR (dan toan)) cau".
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sach) or (hieu quang)) - thanh trung cua nhung cong ((san toan) OR (dan toan)) cau*.