Perhaps you should try some spelling variations:
phuong doan » phuong loan, phuong hoang, huong dan
huong doan » huong dan, huong loan, phuong loan
bien tinh » bi tinh, yen tinh, diep tinh
tranh va » tranh van, trang va, trinh va
va thong » va thuong, va phuong, he thong
phan cau » phan dau, phan cac, phan tu
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 - canh tranh va thong ((huong doan) or (phuong doan)) phan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so bien tinh - canh tranh va thong ((huong doan) OR (phuong doan)) phan cau.
• Adding a wildcard symbol may retrieve word variants: so bien tinh - canh tranh va thong ((huong doan) or (phuong doan)) phan cau*.