Perhaps you should try some spelling variations:
thieu sang » chieu sang, thieu khang, thieu quang
hieu quang » thieu quang, hieu quan, hieu qua
hang hang » nang hang, cang thang, hung thang
cong luan » tong luan, cong tuan, dong luan
va trong » va truong, va thong, va tuong
va tong » va thong, va tuong, va cong

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 (hieu quang)) - hang hang ((va tong) OR (va trong)) cong luan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (hieu quang)) - hang hang ((va tong) OR (va trong)) cong luan van ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) or (hieu quang)) - hang hang ((va tong) OR (va trong)) cong luan van ban".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) or (hieu quang)) - hang hang ((va tong) OR (va trong)) cong luan van ban*.