Perhaps you should try some spelling variations:
thanh trung » thanh tung
chiet tach » chieu sach
hoc chiet » hoc thiet, hoc nhiet, hoc hien
dung cong » dung trong
cong san » cong tac
san phan » san pham, van phan, sat phan
va dung » van dung, va duong, vat dung

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc chiet tach - ((thanh trung) or (canh tranh)) va dung cong san phan tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc chiet tach - ((thanh trung) OR (canh tranh)) va dung cong san phan tu.
• Adding a wildcard symbol may retrieve word variants: hoc chiet tach - ((thanh trung) or (canh tranh)) va dung cong san phan tu*.