全文获取类型
收费全文 | 18466篇 |
免费 | 305篇 |
国内免费 | 737篇 |
专业分类
系统科学 | 964篇 |
丛书文集 | 281篇 |
教育与普及 | 578篇 |
理论与方法论 | 85篇 |
现状及发展 | 82篇 |
研究方法 | 2篇 |
综合类 | 17514篇 |
自然研究 | 2篇 |
出版年
2024年 | 30篇 |
2023年 | 45篇 |
2022年 | 92篇 |
2021年 | 118篇 |
2020年 | 133篇 |
2019年 | 87篇 |
2018年 | 80篇 |
2017年 | 82篇 |
2016年 | 122篇 |
2015年 | 332篇 |
2014年 | 807篇 |
2013年 | 568篇 |
2012年 | 989篇 |
2011年 | 1495篇 |
2010年 | 1202篇 |
2009年 | 1276篇 |
2008年 | 1478篇 |
2007年 | 2081篇 |
2006年 | 1709篇 |
2005年 | 1570篇 |
2004年 | 1189篇 |
2003年 | 1027篇 |
2002年 | 648篇 |
2001年 | 546篇 |
2000年 | 360篇 |
1999年 | 266篇 |
1998年 | 230篇 |
1997年 | 182篇 |
1996年 | 151篇 |
1995年 | 113篇 |
1994年 | 118篇 |
1993年 | 85篇 |
1992年 | 74篇 |
1991年 | 63篇 |
1990年 | 40篇 |
1989年 | 37篇 |
1988年 | 34篇 |
1987年 | 27篇 |
1986年 | 15篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
A fuzzy particle swarm optimization (PSO) on the basis of elite archiving is proposed for solving multi-objective optimization problems. First, a new perturbation operator is designed, and the concepts of fuzzy global best and fuzzy personal best are given on basis of the new operator. After that, particle updating equations are revised on the basis of the two new concepts to discourage the premature convergence and enlarge the potential search space; second, the elite archiving technique is used during the process of evolution, namely, the elite particles are introduced into the swarm, whereas the inferior particles are deleted. Therefore, the quality of the swarm is ensured. Finally, the convergence of this swarm is proved. The experimental results show that the nondominated solutions found by the proposed algorithm are uniformly distributed and widely spread along the Pareto front. 相似文献
93.
Tomohiko SAKAO Nicola NAPOLITANO Massimo TRONCI Erik SUNDIN Mattias LINDAHL 《系统科学与系统工程学报(英文版)》2008,17(3):367-381
A new business concept that offers products and services in a different way of traditional product-sales businesses is getting more attention especially in manufacturing industries. This paper investigates how this new business by means of integration of products and services is achieved in Germany and Italy. In addition, it analyzes the differences according to the company sizes. The results include that this type of business is in many cases motivated by their focus on customers and often consists of physical products and their maintenance. The Italian companies, as opposed to the German ones, often design their physical products specifically for this type of offers. From the analysis based on the size difference, small companies are found to achieve specific design for this type of offers while owning physical products. There do not seem to be any established methods or tools developed to support the development of such offers and within such methods/tools there would be room for more adaptation in form of physical product design. 相似文献
94.
Ying Qin Guozhi Cao Zhi Su 《系统科学与信息学报》2008,6(2):109-117
Environmental problem is one of complicated social problems. According to the level of corporate environmental management, there are many influential factors, and their relations are also complicated. In this paper, we analyzed influential factors of corporate environmental management through consultation of experts. And based on the analysis, we applied interpretative structural modeling(ISM) to classify 13 influential factors into 3 levels. We hope it will be useful for the subsequent research and evaluation of corporate environmental management level. 相似文献
95.
Shaorong Sun Xiaoli Cui 《系统科学与信息学报》2008,6(3):257-274
Taking the institution design of controlling the pollution behavior of enterprises as an example, the symbol system specialized for the design and analysis of behavior management institution is put forward, which predigests the institution design greatly and make the process of institution design much like the engineering design. The measure combination method for improving the parameters of the institution, the arithmetic for calculating the validity of the institution and the arithmetic for calculating the behavior probability of the irrational managed are also put forward, which make the design and analysis technology of behavior management institution more practical. 相似文献
96.
A STAGE-STRUCTURED SI ECO-EPIDEMIOLOGICAL MODEL WITH TIME DELAY AND IMPULSIVE CONTROLLING* 总被引:1,自引:0,他引:1
This paper formulates a robust stage-structured SI eco-epidemiological model with periodic constant pulse releasing of infectious pests with pathogens. The authors show that the conditions for global attractivity of the 'pest-eradication' periodic solution and permanence of the system depend on time delay, hence, the authors call it "profitless". Further, the authors present a pest management strategy in which the pest population is kept under the economic threshold level (ETL) when the pest population is uniformly persistent. By numerical analysis, the authors also show that constant maturation time delay for the susceptible pests and pulse releasing of the infectious pests can bring obvious effects on the dynamics of system. 相似文献
97.
针对公共交通与私家车出行方式并行的双模式交通系统,在考虑不同用户的时间价值情况下,通过引进可交易的道路许可证政策,建立了均衡出行交通模型.研究发现,许可证政策将拥挤产生的交通成本内部化,在缓解交通拥堵的同时,通过经济手段,降低了系统总成本.进一步地,本文证明如果汽车比公交快,那么时间价值较高的人会选择私家车出行;反之,如果公交比汽车快,时间价值相对较高的有车族会选择公交出行.通过与OD收费进行比较,我们得到在收费为正的情况下,许可证政策可以得到与基于OD收费相同的效果.最后,算例结果表明,许可证政策使得部分人选择公交出行的成本更低,达到鼓励公交出行的目的;甚至在许可证发放数量少于临界数量的情况下,选择公交出行的人会获得正收益. 相似文献
98.
A hybrid approach of DEA (data envelopment analysis) and TOPSIS (technique for order performance (preference) by similarity
to ideal solution) is proposed for multiple criteria decision analysis in emergency management. Two DEA-based optimization
models are constructed to facilitate identifying parameter information regarding criterion weights and quantifying qualitative
criteria in TOPSIS. An emergency management case study utilizing data from the Emergency Management Australia (EMA) Disasters
Database is provided to demonstrate the feasibility of the proposed analysis procedure. 相似文献
99.
收益共享协调机制下两阶段供应链提前期压缩的博弈分析 总被引:2,自引:0,他引:2
提前期压缩可以使供应链柔性增大、库存成本减少和供应链收益增加.提前期压缩所增加收益的合理分配对供应链成员间的合作伙伴关系的维护和加强起着关键性作用.建立了基于收益共享协调机制下的Stackelberg博弈模型,在制造商投资柔性设备压缩订货提前期给零售商带来的额外效益在供应链上下游间分享的情形下,分析了提前期压缩和零售商库存管理的决策问题.研究发现:在收益共享协调方式下,零售商先行动公布收益分享比例激励制造商进行合理的订货提前期压缩,供应链整体及上下游的收益均要高于订货提前期压缩前;提前期压缩比例和收益共享比例与零售商的终端需求、订货批量等库存管理参数等有着紧密联系. 相似文献
100.
宁夏银北灌区水资源优化配置模型及应用 总被引:4,自引:1,他引:4
以宁夏银北灌区为例,基于大系统分解协调原理建立了地表水地下水联合运用的递阶优化模型.子系统优化模型采用增量动态规划法求解,协调层利用目标协调法和关联预估法实现全局最优,获得不同约束方案下的时段最优引黄水量、井灌水量、井排水量和运行费用.所建模型及求解方法弥补了以往水资源配置模型只考虑地下水垂向运动,忽略水平运动的不足, 改善了模型的仿真性和决策的可靠性. 相似文献