Perhaps you should try some spelling variations:
khong cong » thong cong, khong cang, chong cong
hieu sang » chieu sang, hieu quang, nhieu tang
hieu lang » chieu sang, hieu quang, nhieu tang
cua khong » hua khong, cua phuong, cua thuong
trang cho » trong cho, trang o, sang cho
hanh ban » thanh ban, hang ban, hanh san
cong ban » cong bang, cong san, cong tan
tran cao » toan cao, tran chau, tranh cac
ban cua » ban quan

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc ((hieu sang) OR (hieu lang)) - hanh ban cua khong cong ban ((tran cao) or (trang cho))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sang) OR (hieu lang)) - hanh ban cua khong cong ban ((tran cao) OR (trang cho)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu sang) OR (hieu lang)) - hanh ban cua khong cong ban ((tran cao) or (trang cho))".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sang) OR (hieu lang)) - hanh ban cua khong cong ban ((tran cao) or (trang cho))*.