Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
tong thong » thong thong, dong thong, cong thong
hieu lang » chieu sang, nhieu tang, hieu van
thong tan » thong than, thong tran, thong tin
canh van » anh van, can van, cach van
cua tong » cua cong, cua dong, cua nong
toan cau » toan cao, toan tap, toan tai
toan ban » van ban
van cua » vang cua, ban cua, dan cua

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 lang) OR (hieu quang)) - canh van cua tong thong tan ((toan cau) or (toan ban))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu lang) OR (hieu quang)) - canh van cua tong thong tan ((toan cau) OR (toan ban)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((hieu lang) OR (hieu quang)) - canh van cua tong thong tan ((toan cau) or (toan ban))".
• Adding a wildcard symbol may retrieve word variants: doc ((hieu lang) OR (hieu quang)) - canh van cua tong thong tan ((toan cau) or (toan ban))*.