Perhaps you should try some spelling variations:
trinh quang » tinh quang, tranh quang, trinh dung
chieu sang » chieu sach, chieu xanh, hieu lang
trinh quan » tinh quang, trinh luat, trinh han
dang toan » dang tran, dan toan, dang thanh
dung toan » dung doanh, dung thang, dung thanh
ho chieu » theo chieu, hoc thieu, doi chieu

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 - hanh ((trinh quang) OR (trinh quan)) dung trong ((dang toan) OR (dung toan)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho chieu sang - hanh ((trinh quang) OR (trinh quan)) dung trong ((dang toan) or (dung toan)) cau~".
• Adding a wildcard symbol may retrieve word variants: ho chieu sang - hanh ((trinh quang) OR (trinh quan)) dung trong ((dang toan) or (dung toan)) cau*.