Perhaps you should try some spelling variations:
duong trong » dung trong
duong cong » dung cong, luong cong, trong cong
thieu xanh » chieu xanh, thien anh, thien danh
hieu manh » chieu xanh, hieu nganh, dieu hanh
tranh cua » doanh cua, manh cua
dan than » dan chan, ban than, van than
than tap » toan tap, han tap, phan tap

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 (hieu manh)) - canh tranh cua ((duong cong) or (duong trong)) dan than tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu xanh) OR (hieu manh)) - canh tranh cua ((duong cong) OR (duong trong)) dan than tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu xanh) OR (hieu manh)) - canh tranh cua ((duong cong) or (duong trong)) dan than tap".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu xanh) OR (hieu manh)) - canh tranh cua ((duong cong) or (duong trong)) dan than tap*.