Perhaps you should try some spelling variations:
thanh trung » thanh tung
thong dung » thong cong, thong thuong
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung tuan, trung cap
cong dung » cuong dung, cong dong, cong luong
toan cao » toan ban, toan tap
ho hieu » ho chieu, hoi hieu, nho hieu
va toan » van toan, bai toan, tap toan

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

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