Perhaps you should try some spelling variations:
cong phuong » cong thuong, cong huong, dong phuong
phuong binh » phuong trinh, phuong anh, chuong trinh
hieu sang » chieu sang, hieu quang, nhieu tang
hieu lang » chieu sang, hieu quang, nhieu tang
trinh cua » tinh cua, trinh quan, trinh luan
binh toan » tinh toan, hinh toan, minh toan
toan tap » toan 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 ((hieu sang) or (hieu lang)) - hanh ((trinh cua) OR (trinh luat)) cong phuong binh toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sang) OR (hieu lang)) - hanh ((trinh cua) OR (trinh luat)) cong phuong binh toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sang) or (hieu lang)) - hanh ((trinh cua) OR (trinh luat)) cong phuong binh toan tap".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) or (hieu lang)) - hanh ((trinh cua) OR (trinh luat)) cong phuong binh toan tap*.