Perhaps you should try some spelling variations:
cong trong » cong thuong, duong trong, cong trinh
chieu sang » chieu sach, chieu xanh, nhieu tang
hieu lang » hieu quang, nhieu tang, hieu van
quang van » quang ban, quan van, quang uan
van cong » van dong, van phong, phan cong
kinh van » dinh van, vinh van, binh van

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 (hieu lang)) - tinh quang van cong trong kinh van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((chieu sang) OR (hieu lang)) - tinh quang van cong trong kinh van ban*.