Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
thieu sang » chieu sang, thieu quang, hieu lang
tong cong » trong cong, cong cong, dung cong
hanh han » hanh nhan, hanh phan, hanh san
cong dan » cong san, cong tan, huong dan
nhan tai » hang tai, van tai, toan tai
va tong » va thong, va tuong, va trong
han va » hang va, hanh va, nhan va

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 (thieu khang)) - hanh han va tong cong dan ((nhan tai) or (doanh tai))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thieu khang)) - hanh han va tong cong dan ((nhan tai) OR (doanh tai)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) OR (thieu khang)) - hanh han va tong cong dan ((nhan tai) or (doanh tai))".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) OR (thieu khang)) - hanh han va tong cong dan ((nhan tai) or (doanh tai))*.