Perhaps you should try some spelling variations:
thieu sang » chieu sang, thieu khang, thieu quang
nhung cong » dung cong, thong cong, hang cong
hoc thieu » toc thieu, hoc hien
trinh vat » trinh van, trinh luat, sinh vat
trinh va » trinh van, trinh ve, trinh vi
cong san » cong tac
than cao » toan cao, than cap, than sao
thai cao » tai cao, thoai cac, thuat cao

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 san ((than cao) OR (thai 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 san ((than cao) OR (thai cao))~".
• Adding a wildcard symbol may retrieve word variants: hoc thieu sang - hanh ((trinh va) or (trinh vat)) nhung cong san ((than cao) OR (thai cao))*.