Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
thanh tinh » thanh binh, nhanh tinh, than kinh
hieu sang » chieu sang, hieu lang, hieu quang
cua nhung » va nhung
tinh cua » trinh cua, sinh cua, tinh chat
dan toan » van toan, dan than, manh toan
van than » van thanh, van thang, van tuan

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 sang) or (hieu qua)) - thanh tinh cua nhung cong ((dan toan) or (van than)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sang) OR (hieu qua)) - thanh tinh cua nhung cong ((dan toan) OR (van than)) cau.
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) or (hieu qua)) - thanh tinh cua nhung cong ((dan toan) or (van than)) cau*.