Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sach » chinh sach, chiet tach, chieu sang
hieu xanh » chieu xanh, hieu manh, hieu nganh
trung van » truong van, trong van, trung va
dong cong » duong cong, dung cong, dang cong
tan toan » tan tran, van toan, dan toan
tap toan » tap doan, tap quan, bai toan

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 xanh) or (chieu sach)) - thanh trung van dong cong ((tan toan) OR (tap toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu xanh) OR (chieu sach)) - thanh trung van dong cong ((tan toan) OR (tap toan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu xanh) or (chieu sach)) - thanh trung van dong cong ((tan toan) OR (tap toan)) cau".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu xanh) or (chieu sach)) - thanh trung van dong cong ((tan toan) OR (tap toan)) cau*.