Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu sang » chieu sang, hieu lang, hieu quang
tranh cua » doanh cua, manh cua
cua nhung » va nhung
doc hieu » toc thieu, hoc thieu, hoc hien
dan phan » doan phan, dan chan, van phan
van chat » cao chat

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 - canh tranh cua nhung cong ((dan phan) or (van chat)) dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sang - canh tranh cua nhung cong ((dan phan) OR (van chat)) dau.
• Adding a wildcard symbol may retrieve word variants: doc hieu sang - canh tranh cua nhung cong ((dan phan) or (van chat)) dau*.