Perhaps you should try some spelling variations:
chieu xanh » chieu sang, chieu tinh, hieu manh
chieu sach » chinh sach, chiet tach, chieu sang
hanh trinh » canh tranh, hanh chinh
nhung cong » thong cong, hang cong, nhung don
dung cong » dung trong
trinh va » trinh van, trinh vat, trinh ve
tap toan » tap doan, tap quan, bai toan
toan cau » toan cao, toan ban, toan tap

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi ((chieu xanh) or (chieu sach)) - hanh trinh va ((nhung cong) OR (dung cong)) tap toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((chieu xanh) OR (chieu sach)) - hanh trinh va ((nhung cong) OR (dung cong)) tap toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi ((chieu xanh) or (chieu sach)) - hanh trinh va ((nhung cong) OR (dung cong)) tap toan cau".
• Adding a wildcard symbol may retrieve word variants: doi ((chieu xanh) or (chieu sach)) - hanh trinh va ((nhung cong) OR (dung cong)) tap toan cau*.