Perhaps you should try some spelling variations:
cong ngang » cong nhan, cong quang, cong lang
thieu sang » chieu sang, thieu khang, thieu quang
hoc thieu » toc thieu, hoc hien
hang cong » dang cong, hang nong, bang cong
tinh cua » trinh cua, sinh cua, tranh cua
toan cau » toan ban, toan tap, toan tai
toan cao » toan ban, toan tap

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