Degree papers are in the Xiamen University Electronic Theses and Dissertations Database. Full texts are available in the following ways: 1. If your library is a CALIS member libraries, please log on http://etd.calis.edu.cn/ and submit requests online, or consult the interlibrary loan department in your library. 2. For users of non-calis member libraries, please mail to etd@xmu.edu.cn for delivery details.