Perhaps you should try some spelling variations:
thieu quang » hieu quang, thien quan, trien quang
thanh trung » thanh tung
thieu sang » chieu sang, thieu khang, hieu lang
tam nhung » tham nhung, cam nhung, nam nhung
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 ((thieu sang) or (thieu quang)) - thanh trung tam nhung ((cong dan) OR (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thieu quang)) - thanh trung tam nhung ((cong dan) OR (cong san)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) or (thieu quang)) - thanh trung tam nhung ((cong dan) OR (cong san)) toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) or (thieu quang)) - thanh trung tam nhung ((cong dan) OR (cong san)) toan cau*.