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
tang luan » dung luan
tang cua » mang cua, hang cua, thong cua
dan toan » van toan, dan than, manh toan
toan cao » toan ban, toan tap
ho hieu » ho chieu, hoi hieu, nho hieu

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 - hanh ((tang cua) OR (tang luan)) ((nhung cong) or (thong cong)) dan toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - hanh ((tang cua) OR (tang luan)) ((nhung cong) OR (thong cong)) dan toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - hanh ((tang cua) OR (tang luan)) ((nhung cong) or (thong cong)) dan toan cao".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - hanh ((tang cua) OR (tang luan)) ((nhung cong) or (thong cong)) dan toan cao*.