Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sang » chieu sach, chieu xanh, hieu lang
cua thong » cua thuong, cua tong, suat thong
cua khong » hua khong, cua phuong, cua thuong
toan phan » thanh phan, toan ban, hoa phan
ho chieu » theo chieu, hoc thieu, doi chieu
tan phan » than phan, van phan, tai phan

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ho chieu sang - thanh trung ((cua thong) OR (cua khong)) cong ((tan phan) OR (toan phan)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho chieu sang - thanh trung ((cua thong) or (cua khong)) cong ((tan phan) OR (toan phan)) cau~".
• Adding a wildcard symbol may retrieve word variants: ho chieu sang - thanh trung ((cua thong) or (cua khong)) cong ((tan phan) OR (toan phan)) cau*.