Perhaps you should try some spelling variations:
hanh truong » hanh trong, anh truong, manh truong
truong quan » trong quan, thong quan, luong quan
hieu lang » chieu sang, hieu quang, nhieu tang
quan dung » quang dung, quan duong, qua dung
hoc hieu » hoc thieu, hoc hien, doc hieu
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
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: hoc hieu lang - hanh truong quan dung ((cong dan) or (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - hanh truong quan dung ((cong dan) OR (cong san)) toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - hanh truong quan dung ((cong dan) or (cong san)) toan cau*.