Perhaps you should try some spelling variations:
thien hieu » thien nhien, thien chien, thien hue
thong cong » trong cong, tong cong, thong thong
hieu lang » chieu sang, hieu quang, nhieu tang
trang va » tran van
cong tac » cong ty
phan cau » phan cac, phan tu, phan lap
phan dau » phan tu, hang dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: thien hieu lang - hanh ((trang va) OR (hang va)) thong cong tac ((phan cau) or (phan dau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thien hieu lang - hanh ((trang va) OR (hang va)) thong cong tac ((phan cau) OR (phan dau))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thien hieu lang - hanh ((trang va) OR (hang va)) thong cong tac ((phan cau) or (phan dau))*".