全文获取类型
收费全文 | 9981篇 |
免费 | 282篇 |
国内免费 | 984篇 |
专业分类
系统科学 | 1126篇 |
丛书文集 | 305篇 |
教育与普及 | 59篇 |
理论与方法论 | 28篇 |
现状及发展 | 115篇 |
综合类 | 9613篇 |
自然研究 | 1篇 |
出版年
2024年 | 31篇 |
2023年 | 64篇 |
2022年 | 110篇 |
2021年 | 141篇 |
2020年 | 134篇 |
2019年 | 105篇 |
2018年 | 121篇 |
2017年 | 143篇 |
2016年 | 157篇 |
2015年 | 239篇 |
2014年 | 425篇 |
2013年 | 375篇 |
2012年 | 545篇 |
2011年 | 642篇 |
2010年 | 499篇 |
2009年 | 611篇 |
2008年 | 628篇 |
2007年 | 819篇 |
2006年 | 734篇 |
2005年 | 676篇 |
2004年 | 595篇 |
2003年 | 525篇 |
2002年 | 464篇 |
2001年 | 351篇 |
2000年 | 282篇 |
1999年 | 248篇 |
1998年 | 195篇 |
1997年 | 202篇 |
1996年 | 178篇 |
1995年 | 160篇 |
1994年 | 185篇 |
1993年 | 126篇 |
1992年 | 111篇 |
1991年 | 93篇 |
1990年 | 85篇 |
1989年 | 103篇 |
1988年 | 62篇 |
1987年 | 42篇 |
1986年 | 21篇 |
1985年 | 14篇 |
1984年 | 1篇 |
1981年 | 4篇 |
1955年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
451.
452.
453.
Conventional artificial fish has some shortages on the interaction with environment, other fish, and the animator. This article proposes a multi-tier interaction control model of artificial fish, realizes the interaction model through integration of virtual reality technology and Markov sequence, and provides a virtual marine world to describe the interaction between artificial fish and the virtual environment and the interaction between the artificial fish and the animator. Simulation results show that the interaction model owns not only the basic characteristics of virtual biology, but also has high trueness interaction function. 相似文献
454.
Participatory Sustainability Impact Assessment: Scientific Policy Advice as a Social Learning Process 总被引:3,自引:3,他引:0
Manuel Gottschick 《Systemic Practice and Action Research》2008,21(6):479-495
This paper deals with the development of scientific policy advice by providing a methodology to foster a social learning process.
The methodology, called participatory Sustainability Impact Assessment (pSIA), aims to structure complex problem situations,
to clarify interests and basic assumptions, to interpret scientific studies, to develop impact assessment, and to explore
sensitivity of uncertainty and lack of information. In pSIA workshops the participants are supposed to build conceptual models
with different modelling methods, like System Dynamics, Value Chain Analysis, and Morphological Analysis. A case study is
presented that describes a workshop series with political as well as academic actors, applying the pSIA approach to an impact
assessment of Economic Partnership Agreements between the European Union and the Eastern and Southern Africa Region.
相似文献
Manuel GottschickEmail: URL: www.agchange.de |
455.
Cardiolipin, the heart of mitochondrial metabolism 总被引:5,自引:0,他引:5
Cardiolipin is a unique phospholipid, which is almost exclusively localized in the mitochondrial inner membrane where it is
synthesized from phosphatidylglycerol and cytidinediphosphate-diacylglycerol. After primary synthesis, the mature acyl chain
composition of cardiolipin is achieved by at least two remodeling mechanisms. In the mitochondrial membrane cardiolipin plays
an important role in energy metabolism, mainly by providing stability for the individual enzymes and enzyme complexes involved
in energy production. Moreover, cardiolipin is involved in different stages of the mitochondrial apoptotic process and in
mitochondrial membrane dynamics. Cardiolipin alterations have been described in various pathological conditions. Patients
suffering from Barth syndrome have an altered cardiolipin homeostasis caused by a primary deficiency in cardiolipin remodeling.
Alterations in cardiolipin content or composition have also been reported in more frequent diseases such as diabetes and heart
failure. In this review we provide an overview of cardiolipin metabolism, function and its role in different pathological
states.
Received 16 January 2008; received after revision 26 February 2008; accepted 26 March 2008 相似文献
456.
权马尔可夫链在河流丰枯状况预测中的应用 总被引:31,自引:1,他引:30
针对河川径流量为相依随机变量的特点,提出了以规范化的各阶自相关系数为权, 用加权的马尔可夫链来预测河流未来丰枯状况的方法, 并通过实例对该方法进行了具体的应用 相似文献
457.
有限资源能力下的供需问题研究 总被引:3,自引:0,他引:3
将 JIT思想引入供需链管理中 ,建立了具有供应能力、运输能力约束的极小化产品成本费用总额的供需问题计划模型 ,并利用易于求解的线性规划模型 ,提出了一个有效的启发式算法 .该算法可以在多种资源能力平衡的前提下 ,找到较优的供应计划. 相似文献
458.
459.
460.
针对可修系统的可靠性、维修性计算问题,运用马尔柯夫过程数学模型对可修系统可用度和可靠度进行数学建模.首先推导出单部件可修系统可用度与可靠度的表达式,在此基础上,推导出工程上常用的两并一备复杂可修系统可用度与可靠度的表达式,总结出求解复杂可修系统稳态可用度的简单方法.两种方法结论一致,为进一步研究可修系统可靠性、维修性提供重要理论依据. 相似文献