Perhaps you should try some spelling variations:
quang thanh » quan thanh, hoang thanh, muong thanh
chieu sang » chieu xanh, hieu lang, nhieu tang
chieu sach » chinh sach, chiet tach, chieu xanh
cong trong » cong thuong, duong trong, cong trinh
trong ca » trong cac, trong nha
tran van » luan van
ca tran » ha tran, ca tra, ca tren

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((chieu sang) or (chieu sach)) - tinh quang thanh cong trong ca tran van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((chieu sang) OR (chieu sach)) - tinh quang thanh cong trong ca tran van.
• Adding a wildcard symbol may retrieve word variants: doc ((chieu sang) or (chieu sach)) - tinh quang thanh cong trong ca tran van*.