Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu manh » chieu xanh, hieu nganh, dieu hanh
trung cua » truong cua, trung tuan, trung cap
tang luan » dung luan
hoc hieu » hoc thieu, hoc hien, doc hieu
dan toan » dan than, manh toan, xuan toan
van toan » van tuan, van tan, van thanh

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc hieu manh - hanh ((trung cua) or (tang luan)) nhung cong ((dan toan) OR (van toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu manh - hanh ((trung cua) OR (tang luan)) nhung cong ((dan toan) OR (van toan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu manh - hanh ((trung cua) or (tang luan)) nhung cong ((dan toan) OR (van toan)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc hieu manh - hanh ((trung cua) or (tang luan)) nhung cong ((dan toan) OR (van toan)) cau*.