Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
chieu sang » chieu sach, chieu xanh, nhieu tang
nhung cong » dung cong, thong cong, nhung don
hieu lang » hieu quang, nhieu tang, hieu van
hang cong » dang cong, hang nong, bang cong
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: ho ((chieu sang) or (hieu lang)) - hanh trinh va ((nhung cong) or (hang cong)) tap toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chieu sang) OR (hieu lang)) - hanh trinh va ((nhung cong) OR (hang cong)) tap toan cau.
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sang) or (hieu lang)) - hanh trinh va ((nhung cong) or (hang cong)) tap toan cau*.