Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
thieu sang » chieu sang, thieu quang, hieu lang
thong cong » trong cong, tong cong, thong thong
ttoan tap » toan tai, toan lap, toan tam
hanh han » hanh nhan, hanh phan, hanh san
va thong » va thuong, va phuong, he thong
cong dan » cong san, cong tan, huong dan
toan tap » toan ban
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 thong cong dan ((ttoan tap) or (toan tap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thieu sang) OR (thieu khang)) - hanh han va thong cong dan ((ttoan tap) OR (toan tap)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thieu sang) OR (thieu khang)) - hanh han va thong cong dan ((ttoan tap) or (toan tap))".
• Adding a wildcard symbol may retrieve word variants: hoc ((thieu sang) OR (thieu khang)) - hanh han va thong cong dan ((ttoan tap) or (toan tap))*.