Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung tuan, dung cua
trung cap » truong cao, trung tam
cong cong » cong dong, trong cong, dung cong
hoc hieu » hoc thieu, hoc hien, doc hieu
cong dan » cong san, cong tan, huong dan
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap

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 ((trung cua) or (trung cap)) cong cong dan than cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - hanh ((trung cua) OR (trung cap)) cong cong dan than cau*.