北京理工大学珠海学院毕业设计（论文） 摘要··········································································41
导论·······································································51
1 研究的对象及其意义·······················································51
11 研究的对象···························································51
12 研究的意义···························································51
2 研究的现状······························································61
21 国内研究现状·························································61
22 国外研究现状·························································71
3 研究内容·································································81
4 创新点与不足·····························································82． 出口现状概述·····················································
