Perhaps you should try some spelling variations:
hieu quang » thieu quang, hieu quan, hieu qua
hieu lang » chieu sang, nhieu tang, hieu van
hanh tang » hanh trang, anh tang, hanh mang
cua thanh » gia thanh, va thanh, ha thanh
tang cua » mang cua, hang cua, tang luan
ndung va » nung va, nhung van, nguong va
toan tap » toan ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo ((hieu lang) OR (hieu quang)) - hanh tang cua thanh ((dung va) or (ndung va)) toan tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo ((hieu lang) OR (hieu quang)) - hanh tang cua thanh ((dung va) OR (ndung va)) toan tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo ((hieu lang) OR (hieu quang)) - hanh tang cua thanh ((dung va) or (ndung va)) toan tap".
• Adding a wildcard symbol may retrieve word variants: theo ((hieu lang) OR (hieu quang)) - hanh tang cua thanh ((dung va) or (ndung va)) toan tap*.