Perhaps you should try some spelling variations:
thuong cong » thong cong, thuong con, thuong dong
thieu sang » chieu sang, thieu khang, thieu quang
hanh sinh » hanh tinh, hanh dinh, hinh sinh
nhan chat » nhan chan, phan chat, chuan chat
ngan nhat » ngan nam, nam nhat, tran nhat
sinh va » sinh vat, tinh va, dinh van

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 - hanh sinh va thuong cong ((nhan chat) or (ngan nhat)) ran~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc thieu sang - hanh sinh va thuong cong ((nhan chat) OR (ngan nhat)) ran*.