Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
hanh trinh » canh tranh, hanh chinh
khong cung » khong cang, khong dung, thong cung
hieu lang » chieu sang, nhieu tang, hieu van
trinh cua » tinh cua, trinh luat, trinh quan
cua khong » hua khong, cua phuong, cua thuong
tam toan » tap toan, tam than, pham toan
ta toan » tap toan, va toan, ta tuan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoi ((hieu lang) OR (hieu quang)) - hanh trinh cua khong cung ((ta toan) or (tam toan)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoi ((hieu lang) OR (hieu quang)) - hanh trinh cua khong cung ((ta toan) OR (tam toan)) ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoi ((hieu lang) OR (hieu quang)) - hanh trinh cua khong cung ((ta toan) or (tam toan)) ban".
• Adding a wildcard symbol may retrieve word variants: hoi ((hieu lang) OR (hieu quang)) - hanh trinh cua khong cung ((ta toan) or (tam toan)) ban*.