Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, nhung don
hanh tang » hanh trang, anh tang, hanh mang
hang cong » dang cong, hang nong, bang cong
ho trieu » mot trieu, 25 trieu, ho chieu
30 trieu » 25 trieu
tang cua » mang cua, hang cua, tang luan
tap toan » tap doan, tap quan, bai toan
toan tap » toan ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((ho trieu) or (30 trieu)) tinh - hanh tang cua ((nhung cong) OR (hang cong)) tap toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho trieu) OR (30 trieu)) tinh - hanh tang cua ((nhung cong) OR (hang cong)) tap toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho trieu) or (30 trieu)) tinh - hanh tang cua ((nhung cong) OR (hang cong)) tap toan tap".
• Adding a wildcard symbol may retrieve word variants: ((ho trieu) or (30 trieu)) tinh - hanh tang cua ((nhung cong) OR (hang cong)) tap toan tap*.