Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
dung duong » dong duong, dung dung, dung luong
hieu sang » chieu sang, hieu quang, nhieu tang
hieu lang » chieu sang, hieu quang, nhieu tang
dung dong » dung cong, vung dong, dung trong
trinh va » trinh van, trinh vat, trinh ve
anh toan » manh toan, anh tuan, thanh 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: doc ((hieu sang) or (hieu lang)) - hanh trinh va ((dung duong) OR (dung dong)) anh toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sang) OR (hieu lang)) - hanh trinh va ((dung duong) OR (dung dong)) anh toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sang) or (hieu lang)) - hanh trinh va ((dung duong) OR (dung dong)) anh toan cau".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) or (hieu lang)) - hanh trinh va ((dung duong) OR (dung dong)) anh toan cau*.