Perhaps you should try some spelling variations:
trung tuan » trung thanh, tran tuan, truong thanh
nhung cong » dung cong, thong cong, hang cong
hieu cach » hieu cac, chieu sach, hieu ca
hoc hieu » hoc thieu, hoc hien, doc hieu
dan toan » van toan, dan than, manh 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 hieu cach - thanh ((trung tuan) OR (trung tam)) nhung cong ((dan toan) or (dan chan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu cach - thanh ((trung tuan) OR (trung tam)) nhung cong ((dan toan) OR (dan chan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu cach - thanh ((trung tuan) OR (trung tam)) nhung cong ((dan toan) or (dan chan)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc hieu cach - thanh ((trung tuan) OR (trung tam)) nhung cong ((dan toan) or (dan chan)) cau*.