Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien danh
thien anh » thien danh, tien anh, thien thanh
hanh tang » hanh trang, anh tang, hanh mang
hang cong » dang cong, bang cong, thanh cong
hang nong » thang long, han tong
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: hoc ((thieu xanh) OR (thien anh)) - hanh tang cua ((hang cong) or (hang nong)) tap toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu xanh) OR (thien anh)) - hanh tang cua ((hang cong) OR (hang nong)) tap toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu xanh) OR (thien anh)) - hanh tang cua ((hang cong) or (hang nong)) tap toan tap".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu xanh) OR (thien anh)) - hanh tang cua ((hang cong) or (hang nong)) tap toan tap*.