Perhaps you should try some spelling variations:
nhung cong » thong cong, hang cong, nhung don
thieu xanh » chieu xanh, hieu manh, thien anh
dung cong » dung trong
dong cua » dung cua, huong cua, thong cua
cong cua » cong cu, huong cua, thong cua
bai toan » bai tap
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: toc thieu xanh - ha ((dong cua) OR (cong cua)) ((nhung cong) or (dung cong)) bai toan ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc thieu xanh - ha ((dong cua) OR (cong cua)) ((nhung cong) OR (dung cong)) bai toan ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc thieu xanh - ha ((dong cua) OR (cong cua)) ((nhung cong) or (dung cong)) bai toan ban".
• Adding a wildcard symbol may retrieve word variants: toc thieu xanh - ha ((dong cua) OR (cong cua)) ((nhung cong) or (dung cong)) bai toan ban*.