Perhaps you should try some spelling variations:
thanh trong » thanh trung, tranh trong, hanh trong
kien sach » vien bach, kien mac, viet sach
dien sach » dien anh
trong van » trong cac
dong cong » duong cong, dung cong, dang cong
dan than » ban than, van than, dan toan
dan chan » dan gian, dan ca, van chat

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((kien sach) or (dien sach)) - thanh trong van dong cong ((dan than) OR (dan chan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((kien sach) OR (dien sach)) - thanh trong van dong cong ((dan than) OR (dan chan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((kien sach) or (dien sach)) - thanh trong van dong cong ((dan than) OR (dan chan)) cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((kien sach) or (dien sach)) - thanh trong van dong cong ((dan than) OR (dan chan)) cao*.