Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
hieu lang » chieu sang, hieu quang, nhieu tang
mang vua » mang cua, bang va, dang va
cong san » cong tac
ho hieu » ho chieu, hoi hieu, nho hieu
mang va » bang va, dang va, mang xa
san van » tan van, luan van, tran van

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 ((((mang va) OR (mang vua))) or (hang va)) thong cong san van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu lang - hanh ((((mang va) OR (mang vua))) OR (hang va)) thong cong san van ban.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho hieu lang - hanh ((((mang va) OR (mang vua))) or (hang va)) thong cong san van ban".
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - hanh ((((mang va) OR (mang vua))) or (hang va)) thong cong san van ban*.