Perhaps you should try some spelling variations:
thieu xanh » chieu xanh, hieu manh, thien anh
hanh trinh » canh tranh, hanh chinh
nhung cong » dung cong, thong cong, nhung don
hoc thieu » toc thieu, hoc hien
trinh cua » tinh cua, trinh luat, trinh quan
hang cong » dang cong, hang nong, bang cong
tap toan » tap doan, tap quan
bai toan » bai 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 - hanh trinh cua ((nhung cong) OR (hang cong)) ((tap toan) or (bai toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu xanh - hanh trinh cua ((nhung cong) OR (hang cong)) ((tap toan) OR (bai toan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu xanh - hanh trinh cua ((nhung cong) OR (hang cong)) ((tap toan) or (bai toan)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc thieu xanh - hanh trinh cua ((nhung cong) OR (hang cong)) ((tap toan) or (bai toan)) cau*.