Presently， the issue of completing a systematic volunteerism has drawn an increasing amount of attention from governments......

【Abstract】Up-star learning master APP is a professional mobile online teaching platform for mobile terminals， which has......

Ⅰ.Introduction　　Ramsey’s theorem is a foundational result in combinatorics. The first version of this result was pro......

【Abstract】With our country’s quick urbanization and modernization， the development of Pu’er’s rural tourism in Yunna......