Perhaps you should try some spelling variations:
hieu lang » chieu sang, hieu quang, nhieu tang
cong cong » cong dong, trong cong, dung cong
doc hieu » toc thieu, hoc thieu, hoc hien
tra xuan » tran xuan, tra quan, tran tuan
tran van » luan van
cong dat » cong dan, dong dat, cong da
dat khan » dat khanh, dat thanh, bat khanh
khan cap » khan ap, than cap, khoan cam

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 lang - thanh ((tra xuan) or (tran van)) cong cong dat khan cap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu lang - thanh ((tra xuan) OR (tran van)) cong cong dat khan cap*.