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