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