全文获取类型
收费全文 | 13895篇 |
免费 | 87篇 |
国内免费 | 370篇 |
专业分类
系统科学 | 1271篇 |
丛书文集 | 277篇 |
教育与普及 | 325篇 |
理论与方法论 | 60篇 |
现状及发展 | 132篇 |
研究方法 | 15篇 |
综合类 | 12272篇 |
出版年
2024年 | 6篇 |
2023年 | 9篇 |
2022年 | 27篇 |
2021年 | 24篇 |
2020年 | 42篇 |
2019年 | 24篇 |
2018年 | 37篇 |
2017年 | 100篇 |
2016年 | 98篇 |
2015年 | 145篇 |
2014年 | 110篇 |
2013年 | 114篇 |
2012年 | 150篇 |
2011年 | 807篇 |
2010年 | 321篇 |
2009年 | 574篇 |
2008年 | 336篇 |
2007年 | 292篇 |
2006年 | 238篇 |
2005年 | 368篇 |
2004年 | 1690篇 |
2003年 | 1257篇 |
2002年 | 1034篇 |
2001年 | 591篇 |
2000年 | 351篇 |
1999年 | 432篇 |
1998年 | 659篇 |
1997年 | 741篇 |
1996年 | 209篇 |
1995年 | 129篇 |
1994年 | 387篇 |
1993年 | 795篇 |
1992年 | 544篇 |
1991年 | 524篇 |
1990年 | 451篇 |
1989年 | 266篇 |
1988年 | 163篇 |
1987年 | 166篇 |
1986年 | 77篇 |
1985年 | 31篇 |
1984年 | 8篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1974年 | 2篇 |
1971年 | 5篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1967年 | 1篇 |
1966年 | 3篇 |
1960年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
61.
肖南峰 《系统工程与电子技术(英文版)》2004,15(2)
A learning-based control approach is presented for force servoing of a robot with vision in an unknown environment. Firstly, mapping relationships between image features of the servoing object and the joint angles of the robot are derived and learned by a neural network. Secondly, a learning controller based on the neural network is designed for the robot to trace the object. Thirdly, a discrete time impedance control law is obtained for the force servoing of the robot, the on-line learning algorithms for three neural networks are developed to adjust the impedance parameters of the robot in the unknown environment. Lastly, wiping experiments are carried out by using a 6 DOF industrial robot with a CCD camera and a force/torque sensor in its end effector, and the experimental results confirm the effecti veness of the approach. 相似文献
62.
肖扬 《系统工程与电子技术(英文版)》2004,15(3)
It is revealed that the dynamic stability of 2-D recursive continuous-discrete systems with interval parameters involves the problem of robust Hurwitz-Schur stability of bivariate polynomials family. It is proved that the Hurwitz-Schur stability of the denominator polynomials of the systems is necessary and sufficient for the asymptotic stability of the 2-D hybrid systems. The 2-D hybrid transformation, i. e. 2-D Laplace-Z transformation, has been proposed to solve the stability analysis of the 2-D continuous-discrete systems, to get the 2-D hybrid transfer functions of the systems. The edge test for the Hurwitz-Schur stability of interval bivariate polynomials is introduced. The Hurwitz-Schur stability of the interval family of 2-D polynomials can be guaranteed by the stability of its finite edge polynomials of the family. An algorithm about the stability test of edge polynomials is given. 相似文献
63.
Atomicity is necessary for reliable and secure electronic commerce transaction and to guarantee the participants' interests. An atomic and efficient e-cash (electronic cash) transaction protocol based on the classical e-cash scheme is presented. The delivery of digital goods is incorporated into the process of payment in the protocol. Apart from ensuring all three levels of atomicity, the novel protocol features high efficiency and practicability with unfavorable strong assumption removed. Furthermore, the proposed protocol provides non-repudiation proofs for any future disputes. At last, analysis of the atomicity and efficiency is illustrated. 相似文献
64.
末制导炮弹的研制现状及发展趋势 总被引:12,自引:0,他引:12
自20世纪末期以来,高新技术大量运用于火炮尤其是弹药的设计和研制中。为了大幅度地提高火炮射击精度,出现了一种将制导技术运用于传统弹药而产生的末制导炮弹。描述了末制导炮弹的制导方式和关键技术,对外军几种典型的末制导炮弹的技术性能进行了简介,总结了末制导炮弹的研制现状及发展趋势。 相似文献
65.
Abstract: The cooperative mechanism is one main issue in the decentralized supply chain system, especially in an asym-metric information structure. We analyze the non-cooperative game behavior of a 2-echelon distribution supply chain,compare the results with the system optimal solution, and give the supplier dominated cooperative mechanisms. We alsoanalyze the validity of our contract under the asymmetric retailers' holding cost information and give some useful conclu-sions. 相似文献
66.
Abstract: A array of the azimuthally averaged range-profile vectors and the inter-class and intra-class divergence matrixesare constructed iwth many frames of the high resolution range profiles which result from radar echoes of airplanes. Takingthe methods of whitening transformation and SVD produces a system of subspace vectors for target recognition. Where-upon, a template library for target recognition is built by the projection of a class-mean vector made from the radar dataonto the subspace for recognition. By Euclidean distance, a comparison is made between the above projection and eachtemplate in the library, to decide which class the target belongs to. Finally, simulations with the experimental radar dataarte given to show that the proposed method is robust to variation in azimuth and immune to additive Gaussian noisewhen SNR≥5dB. 相似文献
67.
Abstract: A novel evolutionary route planner for aircraft is proposed in this paper. In the new planner, individual candi-dates are evaluated with respect to the workspace, thus the computation of the configuration space is not required. By usingproblem-specific chromosome structure and genetic operators, the routes are generated in real time, with different missionconstraints such as minimum route leg length and flying altitude, maximum turning angle, maximum climbing/diving an-gle and route distance constraint taken into account. 相似文献
68.
Non-Minimum Phase Nonlinear System Predictive Control Based on Local Recurrent Neural Networks 总被引:3,自引:0,他引:3
Abstract: After a recursive multi-step-ahead predictor for nonlinear systems based on local recurrent neural networks isintroduced, an intelligent PID controller is adopted to correct the errors including identified model errors and accumulatederrors produced in the recursive process. Characterized by predictive control, this method can achieve a good controlaccuracy and has good robustness. A simulation study shows that this control algorithm is very effective. 相似文献
69.
1 .INTRODUCTIONItisknownthatphysicaloptics(PO)hasbeenwidelyusedinfastpredictionofradarcrosssection (RCS)ofacomplexconductingorcoatedobject.POisadoptedwithoutexceptionamongtheissuedfamouscomputa tionalsoftwareofhigh frequencyEMscatteringbyacomplexobjectsuchasRECOTA[1 ] ,GRECO[2 ,3] ,X PATCH[4] ,whereonlytheisotropiccoatingisconcerned .However,theanisotropiccoatingencoun teredinsomepracticalapplicationsimpelsonetofindthesuitablesolutionforhigh frequencyscatteringbytheobjectcoatedwi… 相似文献
70.
1 .INTRODUCTIONTheabilityofpositioningmobileobjects (MOs) ,in cludingvehiclesandtravelersholdingmobiletermi nals,isafundamentalfunctionforsomeITSsubsys tems,suchasemergencyrescue,securitysystem ,au tomaticnavigationsystem ,andtrafficinducementsystem[1 ] .Atpresent,therearethreedominatingtypes[2 ]ofwirelesspositioningtechnologies,i.e.positioningbasedonsatellites,positioningbasedondedicatedcommunicationsystemsandpositioningbasedonpub liclandwirelesstelecommunicationsystems (PLMTS) ,respe… 相似文献