Perhaps you should try some spelling variations:
thieu sang » chieu sang, thieu khang, thieu quang
nhung cong » thong cong, hang cong, nhung don
hoc thieu » toc thieu, hoc hien
trinh vat » trinh van, trinh luat, sinh vat
dung cong » dung trong
trinh va » trinh van, trinh ve, trinh vi
san than » sang than, san thanh, ban than
than cao » toan cao, thai cao, than cap

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

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