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