Perhaps you should try some spelling variations:
thieu sang » chieu sang, thieu khang, thieu quang
hieu quang » thieu quang, hieu quan, hieu qua
canh trinh » canh tranh, hanh trinh, canh tinh
trong dan » trong dang, trong san, trong tan
thong van » trong van, thong va, thong quan
thanh ban » thanh san, thanh van, thanh bac
trinh va » trinh van, trinh vat, trinh ve
va thong » va thuong, va phuong, he thong

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)) - canh trinh va thong ((trong dan) or (thong van)) thanh ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (hieu quang)) - canh trinh va thong ((trong dan) OR (thong van)) thanh ban.
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) or (hieu quang)) - canh trinh va thong ((trong dan) or (thong van)) thanh ban*.