Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sang » chieu sach, chieu xanh, nhieu tang
cua thuong » cua truong, cua phuong, ca thuong
hieu lang » hieu quang, nhieu tang, hieu van
cua khong » hua khong, cua phuong, cua cong
cong tac » cong ty
tac toan » tap toan, tam toan, hach toan
toan cao » toan ban, toan tap

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

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