Perhaps you should try some spelling variations:
thieu xanh » hieu manh, thien anh, thien danh
chieu xanh » chieu sach, chieu sang, chieu tinh
chinh cua » chinh ca, hinh cua, chinh luan
chinh sua » chinh su, chinh luan, hinh su
trong van » trong cac
van tai » von tai, van tuan
tai tap » bai tap, tai tao, hai 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 (chieu xanh)) - hanh ((chinh cua) OR (chinh sua)) dung trong van tai tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu xanh) OR (chieu xanh)) - hanh ((chinh cua) OR (chinh sua)) dung trong van tai tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu xanh) or (chieu xanh)) - hanh ((chinh cua) OR (chinh sua)) dung trong van tai tap".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu xanh) or (chieu xanh)) - hanh ((chinh cua) OR (chinh sua)) dung trong van tai tap*.