全文获取类型
收费全文 | 16526篇 |
免费 | 925篇 |
国内免费 | 455篇 |
专业分类
系统科学 | 1457篇 |
丛书文集 | 344篇 |
教育与普及 | 223篇 |
理论与方法论 | 341篇 |
现状及发展 | 928篇 |
研究方法 | 47篇 |
综合类 | 14564篇 |
自然研究 | 2篇 |
出版年
2024年 | 63篇 |
2023年 | 130篇 |
2022年 | 195篇 |
2021年 | 209篇 |
2020年 | 140篇 |
2019年 | 39篇 |
2018年 | 782篇 |
2017年 | 792篇 |
2016年 | 503篇 |
2015年 | 262篇 |
2014年 | 304篇 |
2013年 | 283篇 |
2012年 | 600篇 |
2011年 | 1307篇 |
2010年 | 1119篇 |
2009年 | 892篇 |
2008年 | 984篇 |
2007年 | 1284篇 |
2006年 | 408篇 |
2005年 | 466篇 |
2004年 | 446篇 |
2003年 | 436篇 |
2002年 | 372篇 |
2001年 | 353篇 |
2000年 | 403篇 |
1999年 | 663篇 |
1998年 | 533篇 |
1997年 | 619篇 |
1996年 | 512篇 |
1995年 | 442篇 |
1994年 | 425篇 |
1993年 | 343篇 |
1992年 | 334篇 |
1991年 | 320篇 |
1990年 | 262篇 |
1989年 | 227篇 |
1988年 | 207篇 |
1987年 | 129篇 |
1986年 | 81篇 |
1985年 | 30篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1967年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
71.
FROM MANUFACTURING SCHEDULING TO SUPPLY CHAIN COORDINATION:THE CONTROL OF COMPLEXITY AND UNCERTAINTY
Peter B.LUH 《系统科学与系统工程学报(英文版)》2003,12(3):279-297
With time-based competition and rapid technology advancements, effective manufacturingscheduling and supply chain coordination are critical to quickly respond to changing marketconditions. These problems, however, are difficult in view of inherent complexity and variousuncertainties involved. Based on a series of results by the authors, decomposition and coordination byusing Lagrangian relaxation is identified in this paper as an effective way to control complexity anduncertainty.A manufacturing scheduling problem is first formulated within the job shop context withuncertain order arrivals, processing times, due dates, and part priorities as a separable optimizationproblem. A solution methodology that combines Lagrangian relaxation, stochastic dynamicprogramming, and heuristics is developed. Method improvements to effectively solve large problemsare also highlighted. To extend manufacturing scheduling within a factory to coordinate autonomicmembers across chains of suppliers, a decentralized supply chai 相似文献
72.
研究了三聚甲醛合成过程进料浓度、催化剂用量等对副产物(特别是甲酸)生成行为的影响。结果表明,该体系副产物的生成强烈地依赖于反应时间和催化剂硫酸的用量,而与原料浓度的波动无关。在反应-精馏过程的反应器中添加惰性高沸有机物,可有效地缩短反应物的停留时间,提高三聚甲酸的选择性,大大降低快速反应-精馏过程对反应器的设计要求。 相似文献
73.
Zhu Canyan Wang Yiming Yang Huibao & Liu Jiasheng School of Electronics Information Engineering Soochow Univ. Suzhou P.R.China 《系统工程与电子技术(英文版)》2006,17(4):875-882
1. INTRODUCTION As the development of technologies of digital signal processing and integrated circuits, the structure of wireless communication system has been improved. Many schemes for software defined radio (SDR) systems have been developed since 1995, and they can be divided into five tiers of solutions according to their developing history and their definitions[1]. The five tiers are conventional hardware-implemented scheme; software-controlled radio scheme; SDR, that implements m… 相似文献
74.
萃取浮选光度法测定微量钼的研究及应用 总被引:2,自引:0,他引:2
研究了用甲苯萃取浮选Mo(Ⅴ)—SCN~-—Kφ三元络合物的各种条件。在硫酸介质中,紫红色络合物最大吸收波长位于585nm,摩尔吸光系数为2.8×10~5l·mol~(-1)·cm~(-1),钼量在0—10μg/25ml范围内符合比耳定律。大量常见元素均不干扰,40倍的钨(Ⅵ)亦不干扰钼的测定,方法已应用于钨矿中微量钼的测定,其结果令人满意。 相似文献
75.
Shape skeletonization (i.e., medial axis extraction) is powerful in many visual computing applications, such as pattern recognition, object segmentation, registration, and animation. In this paper, the authors expand the use of diffusion equations combined with distance field information to approximate medial axes of arbitrary 3D differential properties. It offers an alternative solids represented by polygonal meshes based on their but natural way for medial axis extraction for commonly used 3D polygonal models. By solving the PDE along time axis, this system can not only quickly extract diffusion-based medial axes of input meshes, but also allow users to visualize the extraction process at each time step. In addition, the proposed model provides users a set of manipulation toolkits to sculpt extracted medial axes, then use diffusion-based techniques to recover corresponding deformed shapes according to the original input datasets. This skeleton-based shape manipulation offers a fast and easy way for animation and deformation of complicated mesh objects. 相似文献
76.
Systemic Intervention in a University Department: Reflections on Arrested Action Research 总被引:1,自引:1,他引:0
Don Houston 《Systemic Practice and Action Research》2008,21(2):133-152
This paper reflects on my experience as an insider researcher attempting to use critical systems ideas and practices to promote
quality improvement in a university engineering department. Reflection is a key part of learning. This paper is intended to
contribute to critically, self-reflective learning for the community of systems practitioners. These reflections on my questions
about participation, ethics, politics of process, and the choices and actions resulting from them may help others to formulate
their own. The complexity of systems practice places substantial demands on the researcher, particularly in the case of insider,
practitioner research. Nevertheless, the exploration of critical systems approaches to critique boundaries and structure ‘problems’
in the core aspects of higher education in locally meaningful ways should continue. While demanding, it still can work to
promote learning about authentic quality. 相似文献
77.
朱尧辰 《国外科技新书评介》2007,(4):14-15
本书是基于作者近年来在美国Illinois大学讲课的讲稿形成的一本群论专著,在目前出版物中首次全面论述研究Coxeter群中组合问题的各种新工具和新技术,基本素材均取自近些年的原始研究论文。为了使本书自封并且能被大学数学系高年级学生接受,作者从关于Coxeter群的最基本知识讲起,由此逐步深入,达到前沿课题,为研究人员解决更深刻、更一般问题架设桥梁。 相似文献
78.
Li XIE Lihua XIE 《系统科学与复杂性》2007,20(2):262-272
We consider the stability of a random Riccati equation with a Markovian binary jump coefficient. More specifically, we are concerned with the boundedness of the solution of a random Riccati difference equation arising from Kalman filtering with measurement losses. A sufficient condition for the peak covariance stability is obtained which has a simpler form and is shown to be less conservative in some cases than a very recent result in existing literature. Furthermore, we show that a known sufficient condition is also necessary when the observability index equals one. 相似文献
79.
朱永贵 《国外科技新书评介》2007,(8):3-3
本书是作者于2000年秋至2001年春在休斯顿大学、瑞斯大学为研究生所作的“概率论与随机过程中的泛函分析方法”专题系列讲座内容组成的,主要包含Hilbert空间、Banach空间、弱拓扑、Banach代数和有界算子半群理论等。此外该书还提供了许多例子和练习,既可以用作教学参考书,又便于读者自学。 相似文献
80.
Lanju XU 《系统科学与复杂性》2007,20(1):30-40
In the present paper, we focus on constructive spherical codes. By employing algebraic geometry codes, we give an explicit construction of spherical code sequences. By making use of the idea involved in the proof of the Gilbert-Varshamov bound in coding theory, we construct a spherical code sequence in exponential time which meets the best-known asymptotic bound by Shamsiev and Wyner. 相似文献