Perhaps you should try some spelling variations:
thieu sang » chieu sang, thieu khang, thieu quang
chieu xanh » chieu sach, chieu sang, chieu tinh
hanh sinh » hanh tinh, hanh dinh, hinh sinh
hang cong » dang cong, hang nong, bang cong
cong vang » cong lang, cong quang, cong ngang
toan tap » toan ban
toan cao » toan ban
sinh va » sinh vat, tinh va, dinh van
va hang » van hang, va nang, va lang

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc ((thieu sang) or (chieu xanh)) - hanh sinh va hang cong vang ((toan tap) or (toan cao))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((thieu sang) OR (chieu xanh)) - hanh sinh va hang cong vang ((toan tap) OR (toan cao)).
• Adding a wildcard symbol may retrieve word variants: toc ((thieu sang) or (chieu xanh)) - hanh sinh va hang cong vang ((toan tap) or (toan cao))*.