Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sang » chieu sach, chieu xanh, hieu lang
hieu quang » thieu quang, hieu quan, hieu qua
thong cong » trong cong, tong cong, thong thong
trung cua » truong cua, trung tuan, trung cap
cua thong » cua thuong, cua khong, cua tong
cong vang » cong lang, cong quang, cong ngang
vang toan » van toan, dang toan, quang toan
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chieu sang) or (hieu quang)) - thanh trung cua thong cong vang toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sang) OR (hieu quang)) - thanh trung cua thong cong vang toan ban.
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sang) or (hieu quang)) - thanh trung cua thong cong vang toan ban*.