Perhaps you should try some spelling variations:
thieu sang » chieu sang, thieu khang, thieu quang
hoc thieu » toc thieu, hoc hien
trinh vat » trinh van, trinh luat, sinh vat
hang cong » dang cong, hang nong, bang cong
trinh va » trinh van, trinh ve, trinh vi
dan toan » van toan, dan than, manh toan
dan chan » dan gian, dan ca, van chat

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 - canh ((trinh va) OR (trinh vat)) hang cong ((dan toan) or (dan chan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thieu sang - canh ((trinh va) OR (trinh vat)) hang cong ((dan toan) OR (dan chan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thieu sang - canh ((trinh va) OR (trinh vat)) hang cong ((dan toan) or (dan chan)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc thieu sang - canh ((trinh va) OR (trinh vat)) hang cong ((dan toan) or (dan chan)) cau*.