Perhaps you should try some spelling variations:
bien tinh » bi tinh, yen tinh, diep tinh
quang cua » quan cua, quang tuan, quang huy
dung cong » dung trong
cong van » cong vang, cong san, song van
van hanh » van thanh, ban hanh, van anh
hanh cap » hanh cac, hanh cat, hanh cad
so bien » mot bien

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

• Performing a fuzzy search may retrieve terms with similar spellings: so bien tinh - than ((quang cua) or (quan luan)) dung cong van hanh cap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so bien tinh - than ((quang cua) OR (quan luan)) dung cong van hanh cap*.