Perhaps you should try some spelling variations:
trong quang » truong quang, thong quang, trong quan
khoa trong » hoa trong, khoa trung, khoang trong
chieu sang » chieu sach, chieu xanh, hieu lang
doi chieu » doc hieu, doi chi, ho chieu
can tranh » tan tran, van ranh, co tranh
quang van » quang ban, quan van, quang uan
cua khoa » chua khoa, sua khoa, qua khoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi chieu sang - ((canh tranh) or (can tranh)) cua khoa trong quang van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi chieu sang - ((canh tranh) OR (can tranh)) cua khoa trong quang van ban.
• Adding a wildcard symbol may retrieve word variants: doi chieu sang - ((canh tranh) or (can tranh)) cua khoa trong quang van ban*.