Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
song trong » cong trong, dong trong, sang trong
trong minh » truong minh, trong kinh, thong minh
hieu lang » chieu sang, hieu quang, nhieu tang
quang qua » quang cua, quang tuan, quang xuan
minh toan » tinh toan, manh toan, minh tuan
toan ban » van ban

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 sach) or (hieu lang)) - tinh quang qua song trong minh toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((chieu sach) OR (hieu lang)) - tinh quang qua song trong minh toan ban*.