Perhaps you should try some spelling variations:
thanh tung » thanh cong
hieu lang » chieu sang, hieu quang, nhieu tang
dung cong » dung trong
hoc hieu » hoc thieu, hoc hien, doc hieu
tung cua » trung cua, tuong cua, dung cua
cua dung » cua dang, cua dong, qua dung
tac toan » tap toan, hach toan, tich toan
tam toan » tap toan, tam than, pham toan

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 - thanh tung cua dung cong ((tac toan) or (tam toan)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc hieu lang - thanh tung cua dung cong ((tac toan) OR (tam toan)) ban.
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - thanh tung cua dung cong ((tac toan) or (tam toan)) ban*.