Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
hieu sang » chieu sang, hieu lang, hieu quang
song danh » song hanh, cong danh, song xanh
doc hieu » toc thieu, hoc thieu, hoc hien
van nang » van quang, van ban, van dong
song dan » song van, cong dan, song da
toan cau » toan cao, toan ban, toan tap

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 - ((tinh toan) or (hanh trinh)) van nang ((song dan) or (song danh)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sang - ((tinh toan) OR (hanh trinh)) van nang ((song dan) OR (song danh)) toan cau.
• Adding a wildcard symbol may retrieve word variants: doc hieu sang - ((tinh toan) or (hanh trinh)) van nang ((song dan) or (song danh)) toan cau*.