Perhaps you should try some spelling variations:
thieu sang » thieu khang, thieu quang, hieu lang
chieu sang » chieu sach, chieu xanh, hieu lang
nhung cong » dung cong, hang cong, nhung don
thong cong » trong cong, tong cong, thong thong
tranh vat » trinh vat, tranh va, tranh van
san toan » van toan, dan toan, manh toan
toan tap » toan ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((thieu sang) or (chieu sang)) - canh tranh vat ((nhung cong) OR (thong cong)) san toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (chieu sang)) - canh tranh vat ((nhung cong) OR (thong cong)) san toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) or (chieu sang)) - canh tranh vat ((nhung cong) OR (thong cong)) san toan tap".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) or (chieu sang)) - canh tranh vat ((nhung cong) OR (thong cong)) san toan tap*.