Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
hoc tieng » hoc hien
hoc bang » hoc bong, hoc tang, hoc dan
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
toan cau » 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 lang - canh tranh ((hoc tieng) or (hoc bang)) ((cong dan) OR (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - canh tranh ((hoc tieng) OR (hoc bang)) ((cong dan) OR (cong san)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - canh tranh ((hoc tieng) or (hoc bang)) ((cong dan) OR (cong san)) toan cau".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - canh tranh ((hoc tieng) or (hoc bang)) ((cong dan) OR (cong san)) toan cau*.