Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu quang » thieu quang, hieu quan, hieu qua
cong thang » cong thanh, cang thang, cong thong
thang hanh » thang thanh, tang hanh, thanh thanh
hieu lang » chieu sang, nhieu tang, hieu van
hanh cac » hang cac, hanh cat, nhanh cay
va bang » va nang, va lang, va hang
va ban » van ban, va bai, va bao

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

• If you are trying to use Boolean operators, they must be ALL CAPS: nho ((hieu lang) OR (hieu quang)) - thanh trung ((va bang) OR (va ban)) cong thang hanh cac~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "nho ((hieu lang) or (hieu quang)) - thanh trung ((va bang) OR (va ban)) cong thang hanh cac~".
• Adding a wildcard symbol may retrieve word variants: nho ((hieu lang) or (hieu quang)) - thanh trung ((va bang) OR (va ban)) cong thang hanh cac*.