Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
hanh trinh » hanh chinh
trong mach » trong cac, trong minh, trong anh
mach toan » manh toan, hach toan, mach tuan
cua dung » cua dang, cua dong, qua dung
toan cao » toan ban, toan tap
ho hieu » ho chieu, hoi hieu, nho hieu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ho hieu quang - ((hanh trinh) or (canh tranh)) cua dung trong mach toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu quang - ((hanh trinh) OR (canh tranh)) cua dung trong mach toan cao.
• Adding a wildcard symbol may retrieve word variants: ho hieu quang - ((hanh trinh) or (canh tranh)) cua dung trong mach toan cao*.