Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu quang » thieu quang, hieu quan, hieu qua
khong cang » thong cong, hong bang, khong dung
theo hieu » theo chieu, theo tieu, thien hieu
cua khong » hua khong, cua phuong, cua thuong
cang tac » cong tac, canh tac, sang tac
toan cau » toan cao, toan tap, toan tai
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: theo hieu quang - ((thanh trung) or (nhanh quang)) cua khong cang tac ((toan cau) OR (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo hieu quang - ((thanh trung) OR (nhanh quang)) cua khong cang tac ((toan cau) OR (toan ban)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo hieu quang - ((thanh trung) or (nhanh quang)) cua khong cang tac ((toan cau) OR (toan ban))".
• Adding a wildcard symbol may retrieve word variants: theo hieu quang - ((thanh trung) or (nhanh quang)) cua khong cang tac ((toan cau) OR (toan ban))*.