全文获取类型
收费全文 | 9430篇 |
免费 | 355篇 |
国内免费 | 900篇 |
专业分类
系统科学 | 872篇 |
丛书文集 | 515篇 |
教育与普及 | 6篇 |
理论与方法论 | 4篇 |
现状及发展 | 57篇 |
综合类 | 9228篇 |
自然研究 | 3篇 |
出版年
2024年 | 11篇 |
2023年 | 32篇 |
2022年 | 82篇 |
2021年 | 102篇 |
2020年 | 109篇 |
2019年 | 112篇 |
2018年 | 93篇 |
2017年 | 132篇 |
2016年 | 156篇 |
2015年 | 217篇 |
2014年 | 345篇 |
2013年 | 319篇 |
2012年 | 522篇 |
2011年 | 502篇 |
2010年 | 413篇 |
2009年 | 513篇 |
2008年 | 534篇 |
2007年 | 710篇 |
2006年 | 646篇 |
2005年 | 570篇 |
2004年 | 553篇 |
2003年 | 471篇 |
2002年 | 403篇 |
2001年 | 364篇 |
2000年 | 345篇 |
1999年 | 326篇 |
1998年 | 257篇 |
1997年 | 245篇 |
1996年 | 241篇 |
1995年 | 216篇 |
1994年 | 181篇 |
1993年 | 181篇 |
1992年 | 169篇 |
1991年 | 142篇 |
1990年 | 127篇 |
1989年 | 120篇 |
1988年 | 103篇 |
1987年 | 70篇 |
1986年 | 37篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1981年 | 1篇 |
1955年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
941.
研究了碳化钨(WC)增强钢基复合材料在980~1240℃温度范围的高温奥氏体化行为及相应的淬火硬化效应.发现此材料的奥氏体化温度范围宽,在980~1100℃加热淬火均能得到细小的组织结构,而且具有显著的淬火硬化效果(HRC68).并且测量及探讨了不同状态下大块硬质相、WC聚集区及基体显微硬度(HV0.05)的变化以及与宏观洛氏硬度之间的关系. 相似文献
942.
XU Zeshui 《系统科学与系统工程学报(英文版)》1998,(4)
1IntroductionTheanalytichierarchyprocess(AHP)hasfoundwidespreadapplicationindecisionmakillgproblemsinvolvingmultiplecriteriainsystemsofmanylevels,andforPriority-modelingincomplexsystems.Preferellcesforasetofobjects(proje(its,prodllcts,etc.)area'~ryoftollexpressedintheformofpairwise(}olllparisolls.Thisisparticularlytrueinmarketresear(}11situationwhereconsumerpreferencesforasetofproductsaretobecaptured.Thepl'oblemistoextractfromthepairwisedataasetofratingsorweightsfortilenobjects.Inthismannera… 相似文献
943.
1. INTRODUCTIONPhysical plaaes are inevitably affected by exogenous disturbance, hence rejecting disturbanceis important. Ffor example, HOO-control systems can reject the LZ disturbance. But in factthere are maily species of disturbances: some are LZ-attenuation; some are stochastic; andsome are Loo(loo) [6]. If the exogenous disturbance is modeled as the energy-bounded signal, and the performance is the output energyt that is Hoo problem. If the performance isoutput energy, that is p… 相似文献
944.
Jinguang Liu 《系统科学与信息学报》2009,7(4):351-358
Command Decision Simulation (CDS) is not only an important and difficult issue in the field of simulation, but also a technique issue to be tackled in the course of collective Modeling and Simulation in Joint Operations Experiment Center. CDS can give support to all kinds of simulation. Using computer to realize the Blue side's command deci- sion automatic execution in the operation training simulation system can improve training effect. Using computer to realize the lower level command unit's automatic command deci- sion can help to reduce the number of controllers and release them from heavy work. It can also enlarge simulation scale and increase the freedom of the simulation entity especially the command entity, thus enhance the authenticity and credibility of the simulation. Ac- cording to the command decision structure and the Joint Intention Theory, the thesis puts forward the method of making use of Coordination Matrix (CM) to realizing cooperation among the entities in CDS and constructs the calculation sketch of Task Execution, Task Monitoring and Task Replanning. At the same time, the thesis brings forward the CDS structure vision based on Partial Global Planning(PGP). As CM is an indispensable part of combat simulation, the theory and the method of CDS will become an important part for the theory of Combat Simulation. 相似文献
945.
1,Illtroduction'SincetheearlypapersbyG0ppa[1-31,algebralc-ge0metriccodeshavebeeninthespotlight0fcodingthe0reticresearchf0rab0uttwodecades.NumerousexcitingresultshavebeenachievedusingGoppa'sconstructi0noflinearcodesfromalgebralccurvesoverfinitefields,bothbyalgebraicge0metorsandcodingtheorists.Becauseofthedifficultyofthesubject,severalexplanatorypaPersandtextbookshaveappeared,seeforinstance[4-8].Inthispaperwepresentaquitedtherentpointofviewconcerningalgebraic-geometriccodes.Itiswellknownthataq… 相似文献
946.
对一种改进层次分析法误导的理论分析 总被引:4,自引:2,他引:2
揭示了基于最优传递矩而建立的改进层次分析法产生误导的原因,从理论上否定了该法的一些错误论断。 相似文献
947.
The fault detection problem for the nonlinear networked control system(NCS) with packet dropout and delay is investigated.A nonlinear stochastic system model is proposed to account for the NCS with random packet dropout and networkinduced non-uniformly distributed time-varying delay in both from sensor to controller(S/C) and from controller to actuator(C/A).Based on the obtained NCS model,employing an observer-based fault detection filter as the residual generator,the addressed fault detection problem is converted into an auxiliary nonlinear H∞ control problem.Then,with the help of Lyapunov functional approach,a sufficient condition for the desired fault detection filter is constructed in terms of certain linear matrix inequalities,which depend on not only the delay interval but also the delay interval occurrence rate and successful packet communication rate.Especially,a trade-off phenomenon between the maximum allowable delay bound and successful data packet transmission rate is found,which is typically resulted from the limited bandwidth of communication networks.The effectiveness of the proposed method is demonstrated by a simulation example. 相似文献
948.
The fault detection problem for the nonlinear networked control system (NCS) with packet dropout and delay is investigated.A nonlinear stochastic system model is proposed to account for the NCS with random packet dropout and networkinduced non-uniformly distributed time-varying delay in both from sensor to controller (S/C) and from controller to actuator (C/A).Based on the obtained NCS model,employing an observer-based fault detection filter as the residual generator,the addressed fault detection problem is converted into an auxiliary nonlinear H∞ control problem.Then,with the help of Lyapunov functional approach,a sufficient condition for the desired fault detection filter is constructed in terms of certain linear matrix inequalities,which depend on not only the delay interval but also the delay interval occurrence rate and successful packet communication rate.Especially,a trade-off phenomenon between the maximum allowable delay bound and successful data packet transmission rate is found,which is typically resulted from the limited bandwidth of communication networks.The effectiveness of the proposed method is demonstrated by a simulation example. 相似文献
949.
1 IntroductionThe Analytic Hierarchy Process(AHP) ,introduced by Saaty[7] ,is one of the popular andpowerful technique for decision making,and has also been applied to group decisionproblems(Hannan[2 ] ,Khorramshahgol and Moustakis[5] ,Islei and Lockett[3] ) .TheWeighted Arithmetic Mean Method (WAMM) and Weighted Geometric Mean Method(WGMM) are the mostcommon group preference aggregation methods in AHP.In orderto use the WAMM and WGMM,one has to find the weights to be assigned… 相似文献
950.
FU Yu-sun TIAN Zuo-hua SHI Song-jiaoDepartment of Automation Shanghai Jiaotong University Shanghai China 《系统科学与系统工程学报(英文版)》2001,10(2)
1 IntroductionSince the notion of dissipative system was introduced by Willems ( 1 972 a) [1 ] ,andsubsequently generalized by Hill and Moylan( 1 980 ) [2 ] ,it has played an important role insystems,circuits,and control.Dissipativeness is a generalization of the concept ofpassivity in electrical network and otherdynamical systems which dissipate energy in someabstract sense.Applications of dissipativeness in the stability analysis of linear systemswith certain nonlinear feedback were first… 相似文献