Perhaps you should try some spelling variations:
thieu khang » chieu khong, thieu quang
thieu sang » chieu sang, thieu quang, hieu lang
nhung cong » dung cong, thong cong, hang cong
tranh va » tranh van, trang va, trinh va
cong dan » cong san, cong tan, huong dan
phan cau » phan cac, phan tu, phan lap
phan dau » phan tu, hang dau

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