全文获取类型
收费全文 | 11302篇 |
免费 | 803篇 |
国内免费 | 259篇 |
专业分类
系统科学 | 1334篇 |
丛书文集 | 201篇 |
教育与普及 | 185篇 |
理论与方法论 | 286篇 |
现状及发展 | 904篇 |
研究方法 | 19篇 |
综合类 | 9435篇 |
出版年
2024年 | 33篇 |
2023年 | 83篇 |
2022年 | 101篇 |
2021年 | 131篇 |
2020年 | 86篇 |
2019年 | 28篇 |
2018年 | 762篇 |
2017年 | 794篇 |
2016年 | 486篇 |
2015年 | 177篇 |
2014年 | 229篇 |
2013年 | 162篇 |
2012年 | 430篇 |
2011年 | 1179篇 |
2010年 | 995篇 |
2009年 | 712篇 |
2008年 | 756篇 |
2007年 | 1020篇 |
2006年 | 211篇 |
2005年 | 267篇 |
2004年 | 266篇 |
2003年 | 293篇 |
2002年 | 197篇 |
2001年 | 169篇 |
2000年 | 195篇 |
1999年 | 326篇 |
1998年 | 290篇 |
1997年 | 333篇 |
1996年 | 269篇 |
1995年 | 249篇 |
1994年 | 211篇 |
1993年 | 212篇 |
1992年 | 149篇 |
1991年 | 138篇 |
1990年 | 127篇 |
1989年 | 104篇 |
1988年 | 96篇 |
1987年 | 56篇 |
1986年 | 30篇 |
1985年 | 10篇 |
1984年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
<正> In this paper,an equivalency condition of nonsingularity in nonlinear semidefinite programming,which can be viewed as a generalization of the equivalency condition of nonsingularity for linearsemidefinite programming,is established under certain conditions of convexity. 相似文献
122.
<正> It is presented in this paper that the new design and its analysis of finite difference domaindecomposition algorithms for the two-dimensional heat equation,and the numerical results have shownthe stability and accuracy of the algorithms,where Saul'yev asymmetric schemes have been used atthe interface points.The Algorithm Ⅱ in this paper has further extended those developed by Dawsonand the others,Zhang and Shen. 相似文献
123.
<正> A family of integral-type goodness-of-fit tests is investigated.This family includes someexisting tests,such as the Cramér-von Mises test and Anderson-Darling test,etc.The asymptoticdistributions of the tests in the family under the null and local alternative hypotheses are established.The almost sure convergence under a fixed underlying distribution is obtained.Furthermore,simulationsare conducted to compare the powers of the tests in the family.Simulation results show that fordifferent alternatives,the more powerful tests are different,and the parameter λ has great influence onthe tests in small sample cases. 相似文献
124.
The reverse construction and analysis of the networks of molecular interactions are essential for understanding their functions
within cells. In this paper, a logic network model is constructed to investigate the complicated regulation mechanism of shoot
genes of Arabidopsis Thaliana in response to stimuli. The dynamics of the complicated logic network is analyzed, discussed,
and simulated. The simulation results show that the logic network of the active genes of shoot eventually evolves into eleven
attractors under the stimuli, including five 1-periodic and six 2-periodic attractors. Our work provides valuable reference
and guidance for biologists to understand and explain Arabidopsis’ response to external stimuli by experiments. 相似文献
125.
The approach of available transfer capability (denoted as ATC) incorporating wind generation has been paid very high attention since the development of wind generation. Based on the maximum function, this paper presents an ATC model. The characteristic of the new model is twofold. First, it considers wind turbines connected to power system and static security of power system simultaneously. Second, it is a system of semismooth equations and can be solved easily. By using the smoothing strategy, a smoothing Newton method is adopted for solving the proposed new ATC model. Numerical simulation results of the IEEE 30-bus and 118-bus system show that the new model and algorithm are feasible and effective. The impact of wind turbines connected to power system on ATC is also analyzed. 相似文献
126.
<正> This paper considers finite-time χ-consensus problem for a multi-agent system with firstorderindividual dynamics and switching interaction topologies.Several distributed finite-time consensusrules are constructed for multi-agent dynamics in a unified way with the help of Lyapunovfunction and graph theory as well as homogeneity.Time-invariant non-smooth forms of finite-timeneighbor-based controllers are proposed and a numerical example is shown for illustration. 相似文献
127.
<正> This paper analyzes performance of optimal channel estimation and multiuser detection(MUD) in a block-fading code-division multiple-access (CDMA) channel on the assumptions of randomspreading and large-system limit,by using the replica method developed in statistical mechanics.The authors find that the asymptotic spectral efficiency of the linear minimum mean-squared error(LMMSE) MUD which was proposed and analyzed by Evans and Tse in 2000 is indistinguishable fromthat of the optimal MUD for small system loads.Our results imply that performance of MUD scarcelyimproves even if one spends more computational cost than that of the LMMSE MUD,i.e.,at most thecube of the number of users,on the above-described conditions. 相似文献
128.
<正> This paper considers the problem of actuator failure compensation for a class of nonlinearsystems in the form of output-feedback.MT-filters are exploited to estimate the unmeasured states.The backsteppping technique is used to construct the controller recursively.The proposed compensationscheme can grantee the boundedness of all the closed-loop signals and asymptotic output tracking.Thetheoretical results are illustrated by a simulation example. 相似文献
129.
<正> This paper discusses the null boundary controllability of two PDE's,modeling a compositesolid with different physical properties in each layer.Interface conditions are imposed. 相似文献
130.
<正> This paper formulates and analyzes a line search method for general nonlinear equalityconstrained optimization based on filter methods for step acceptance and secant methods for searchdirection.The feature of the new algorithm is that the secant algorithm is used to produce a searchdirection,a backtracking line search procedure is used to generate step size,some filtered rules areused to determine step acceptance,second order correction technique is used to reduce infeasibility andovercome the Maratos effect.Global convergence properties of this method are analyzed:under mildassumptions it is showed that every limit point of the sequence of iterates generated by the algorithmis feasible,and that there exists at least one limit point that is a stationary point for the problem.Moreover,it is also established that the Maratos effect can be overcome in our new approach by addingsecond order correction steps so that fast local superlinear convergence to a second order sufficient localsolution is achieved.Finally,the results of numerical experiments are reported to show the effectivenessof the line search filter secant method. 相似文献