Perhaps you should try some spelling variations:
chieu sang » chieu sach, chieu xanh, hieu lang
hieu quang » thieu quang, hieu quan, hieu qua
nhung cong » dung cong, thong cong, hang cong
trinh cua » tinh cua, trinh quan, trinh luan
cong hach » cong sach, cong thanh, cong khanh
hach toan » thanh toan, manh toan
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 sang) or (hieu quang)) - hanh ((trinh cua) OR (trinh luat)) nhung cong hach toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((chieu sang) OR (hieu quang)) - hanh ((trinh cua) OR (trinh luat)) nhung cong hach toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((chieu sang) or (hieu quang)) - hanh ((trinh cua) OR (trinh luat)) nhung cong hach toan ban".
• Adding a wildcard symbol may retrieve word variants: doc ((chieu sang) or (hieu quang)) - hanh ((trinh cua) OR (trinh luat)) nhung cong hach toan ban*.