Perhaps you should try some spelling variations:
nhung cong » dung cong, hang cong, nhung don
thong cong » trong cong, tong cong, thong thong
hieu lang » chieu sang, hieu quang, nhieu tang
trung cap » truong cao, trung tam
nho hieu » nha hieu, nho sieu, nhu hieu
trung ha » trung hoc, trung tam
bai toan » bai tap
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: nho hieu lang - thanh ((trung ha) or (trung cap)) ((nhung cong) OR (thong cong)) bai toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: nho hieu lang - thanh ((trung ha) OR (trung cap)) ((nhung cong) OR (thong cong)) bai toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "nho hieu lang - thanh ((trung ha) or (trung cap)) ((nhung cong) OR (thong cong)) bai toan cao".
• Adding a wildcard symbol may retrieve word variants: nho hieu lang - thanh ((trung ha) or (trung cap)) ((nhung cong) OR (thong cong)) bai toan cao*.