被子植物精细胞分离和特性研究进展

精细胞分离是研究雄性生殖发育的前提之一,近半个世纪以来,人们运用不断更新的生物实验技术,对被子植物精细胞开展了分离及细胞分子特征的研究。分析被子植物精细胞分离方法,总结精细胞二型性与倾向性、细胞融合方面的研究成果,并对其研究意义和前景进行讨论。     

以用户为中心的数字图书馆用户界面设计研究

以用户为中心是数字图书馆的发展方向之一,而用户界面是连接用户与数字图书馆的重要桥梁.用户界面设计是否友好、是否合理,将直接影响数字图书馆系统的使用效率.文章在借鉴前人研究成果的基础上,首先从以用户为中心设计思想出发,总结出研究数字图书馆用户的必要性,然后论述了用户界面设计的理念及用户界面发展的历程,最后从用户的层面上结合具体的实例分析,对数字图书馆用户界面的设计提出几点建议,把以用户为中心的思想真正运用到我国数字图书馆用户界面的建设中去.     

互联网上重要临床医学网址简介

本文对文献计量学统计分析出来的四个综合性临床医学网站的结构、使用和特点加以评价和介绍     

基于动态能力的企业竞争优势培育

简述了企业动态能力的基本概念,指出知识是企业动态能力的核心本质,论述了战略定位和路径是培育企业竞争优势的基础,并提出了培育企业竞争优势的方法。     

我国科技人员自引现象分析

0引言 自引现象是科学著文过程中比较普遍的现象,R.Tagliacozzo和A.Dimitroff分别于1977年和1995年研究了自然科学文献和图书情报学文献的自引现象[1,2].Tagliacozzo的研究表明植物生理学论文自引率为16.6%,神经生理学论文的自引率为17.5%,并且发现自引引文"年龄更青".他认为自引现象与合著者多少、著文作者的文献书目内容多少或论文量是无关的.     

Gasless laparoscopy for benign gynecological diseases using an abdominal wall-lifting system

Objectives: The use of gasless laparoscopy with an abdominal wall-lifting device for benign gynecological diseases was compared to conventional laparoscopy with CO_2 pneumoperitoneum. Methods: From February 2007 to July 2007, 76 women with uterine and/or adnexal benign diseases and candidates for laparoscopic surgery were recruited in this study. Thirty-two women underwent gasless laparoscopic surgery and 44 women underwent pneumoperitoneum laparoscopic surgery. Results: Diverse pathologies, including adnexal cyst, uterine myoma and ectopic pregnancy, were treated successfully with gasless laparoscopic surgery. Compared with the patients in the pneumoperitoneum group, the similar hospital stay (P=0.353) and in-traoperative blood loss (P=0.157) were observed. However, the mean operative time in the gasless group was significantly longer than that in the pneumoperitoneum group (P=0.003). No severe intraoperative or postoperative complications were found in either group, except for one case of laparotomic conversion in the pneumoperitoneum group due to dense pelvic adhesions. The total hospital charges were significantly less in the gasless group than in the pneumoperitoneum group (P=0.001). In 38 cases of ovarian cyst resection, the mean operative time in the gasless group remained longer than that in the pneumoperitoneum group (P=0.017). The total hospital charges were also significantly less in the gasless group than in the pneumoperitoneum group (P<0.001). Con-clusion: Our preliminary results demonstrated that the laparoscopic procedure using the gasless technique was a safe, effective method to treat benign gynecological diseases. Moreover, it was easy to master. As a minimally invasive treatment, gasless laparoscopic surgery provides a good choice to patients in the undeveloped regions in China without increasing the patients' and the government's burden significantly.     

浅谈网页制作教学中的“任务设计”

网页制作是计算机专业课中的一门实践性、操作性、综合性较强的课程。我在教学过程中,针对这门课程的特点,采用＂任务驱动法＂进行教学,收到了很好的教学效果。其间,我也体会到了＂任务设计＂在＂任务驱动法＂教学实施中的重要性。     

二三十年代农村合作社借贷资金的构成及其来源——20世纪前期中国乡村社会变迁研究

在二三十年代出现的农村合作运动，被认为是“救治农村”的有效方法之一，但是，从合作社借贷资金的来源与构成状况上，我们可以看到合作社的社内资金极其微小，转而不得不依赖于社外资金，而社外资金对于农村合作社的支撑又极不稳定，从而无法保障农村合作乃至农村经济的复苏，这从一个侧面反映了当时中国乡村社会变迁的实况。     

网络知识产权犯罪的法律适用及对策研究

伴随着数字经济时代的到来,网络大数据给社会经济、文化各个方面带来巨大经济红利的同时,网络知识产权犯罪也相伴而生.网络知识产权犯罪与传统知识产权犯罪既有共性又有个性,本文结合典型案例展开分析,从网络知识产权犯罪的特点、内涵入手,分析检察机关办理网络知识产权犯罪案件的现实困境,结合网络知识产权犯罪的特殊性探讨其法律适用和司法对策,从加强知识产权检察集中统一履行职能、完善知识产权立法和司法解释、完善网络知识产权犯罪的认定标准等多角度提出建议,以助于保护知识产权、鼓励创新,进而维护公平公正的市场竞争秩序.     

Numerical Study on Helical Fiber Fragmentation in Chiral Biological Materials

Chiral microstructures exist widely in natural biological materials such as wood, bone, and climbing tendrils. The helical shape of such microstructures plays an important role in stress transfer between fiber and matrix,and in the mechanical properties of biological materials. In this paper, helical fiber fragmentation behavior is studied numerically using the finite-element method(FEM), and then, the effects of helical shape on fiber deformation and fracture,and the corresponding mechanical mechanisms are investigated. The results demonstrate that, to a large degree, the initial microfibril angle(MFA) determines the elastic deformation and fracture behavior of fibers. For fibers with a large MFA, the interfacial area usually has large values, inducing a relatively low fragment density during fiber fragmentation. This work may be helpful in understanding the relationship between microstructure and mechanical property in biological materials, and in the design and fabrication of bio-inspired advanced functional materials.