Perhaps you should try some spelling variations:
bien tinh » bi tinh, yen tinh, diep tinh
hanh tang » hanh trang, anh tang, hanh mang
cua khong » hua khong, cua phuong, cua thuong
tang cua » mang cua, hang cua, tang luan
cong dan » cong san, cong tan, cong dong
toan cao » toan ban, toan tap
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 - hanh tang cua khong ((cong dan) or (huong dan)) toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so bien tinh - hanh tang cua khong ((cong dan) OR (huong dan)) toan cao*.