全文获取类型
收费全文 | 12608篇 |
免费 | 953篇 |
国内免费 | 1265篇 |
专业分类
化学 | 2833篇 |
晶体学 | 69篇 |
力学 | 611篇 |
综合类 | 228篇 |
数学 | 9164篇 |
物理学 | 1921篇 |
出版年
2024年 | 10篇 |
2023年 | 119篇 |
2022年 | 150篇 |
2021年 | 193篇 |
2020年 | 265篇 |
2019年 | 315篇 |
2018年 | 302篇 |
2017年 | 346篇 |
2016年 | 362篇 |
2015年 | 250篇 |
2014年 | 520篇 |
2013年 | 987篇 |
2012年 | 594篇 |
2011年 | 715篇 |
2010年 | 578篇 |
2009年 | 805篇 |
2008年 | 817篇 |
2007年 | 841篇 |
2006年 | 697篇 |
2005年 | 630篇 |
2004年 | 555篇 |
2003年 | 525篇 |
2002年 | 480篇 |
2001年 | 457篇 |
2000年 | 415篇 |
1999年 | 373篇 |
1998年 | 349篇 |
1997年 | 325篇 |
1996年 | 268篇 |
1995年 | 224篇 |
1994年 | 203篇 |
1993年 | 135篇 |
1992年 | 138篇 |
1991年 | 114篇 |
1990年 | 113篇 |
1989年 | 78篇 |
1988年 | 65篇 |
1987年 | 60篇 |
1986年 | 56篇 |
1985年 | 55篇 |
1984年 | 49篇 |
1983年 | 29篇 |
1982年 | 53篇 |
1981年 | 40篇 |
1980年 | 27篇 |
1979年 | 35篇 |
1978年 | 31篇 |
1977年 | 22篇 |
1976年 | 24篇 |
1973年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
Guy Bayada 《Journal of Mathematical Analysis and Applications》2003,282(1):212-231
The asymptotic behaviour of a Stokes flow with Tresca free boundary friction conditions when one dimension of the fluid domain tends to zero is studied. A specific Reynolds equation associated with variational inequalities is obtained and uniqueness is proved. 相似文献
43.
Halszka TutajGasiska 《Mathematische Nachrichten》2003,257(1):108-116
44.
风力发电机组变速恒频控制系统研究 总被引:2,自引:0,他引:2
全面介绍了一种最新应用于风力发电中的新型电机—无刷双馈电机,并分析了这种新型电机作变速恒频运行的原理并对这种电机进行了动态特性仿真研究,给出了形式简洁的控制方程和易于实现的控制方案。 相似文献
45.
YaoKui ChenZhixiang 《分析论及其应用》2003,19(2):115-120
This paper gives the weighted Lp convergence rate estimations of the Gruenwald interpolatory polynomials based on the zeros of Chebyshev polymomials of the first kind,and proves that the order of the estimations is optimal for p≥1. 相似文献
46.
Kurt Majewski 《Queueing Systems》2005,50(2-3):199-230
We consider multiclass feedforward queueing networks under first in first out and priority service disciplines driven by long-range dependent arrival and service time processes. We show that in critical loading the normalized workload, queue length and sojourn time processes can converge to a multi-dimensional reflected fractional Brownian motion. This weak heavy traffic approximation is deduced from a deterministic pathwise approximation of the network behavior close to constant critical load in terms of the solution of a Skorokhod problem. Since we model the doubly infinite time interval, our results directly cover the stationary case.AMS subject classification: primary 90B15, secondary 60K25, 68M20 相似文献
47.
48.
Yousef Bisabr 《International Journal of Theoretical Physics》2004,43(10):2137-2148
We investigate a conformal invariant gravitational model which is taken to hold at early universe. The conformal invariance allows us to make a dynamical distinction between the two unit systems (or conformal frames) usually used in cosmology and elementary particle physics. In this model we argue that when the universe suffers phase transition, the resulting mass scale introduced by particle physics should have a variable contribution to vacuum energy density. This variation is controlled by the conformal factor which is taken as a dynamical field. We then deal with the cosmological consequences of this model. In particular, we shall show that there is an inationary phase at early times. At late times, on the other hand, it provides a mechanism which makes a large effective cosmological constant relax to a sufficiently small value. Moreover, we shall show that the conformal factor acts as a quintessence field that leads the universe to accelerate at late times. 相似文献
49.
One of the most ignored, but urgent and vital challenges confronting society today is the vulnerability of urban areas to extreme events. Current organization of response systems, predominantly based on a command and control model, limits their effectiveness and efficiency. Particularly, in decision‐making processes where a large number of actors may be involved. In this article, a new distributed collaborative decision‐making model is proposed to overcome command and control limitations encountered in stressful, hostile, chaotic, and large‐scale settings. This model was derived by borrowing concepts from the collective decision making of honeybees foraging, a successful process in solving complex tasks within complex settings. The model introduced in this article was evaluated through differential equations, i.e., continuous analysis, and difference equations, i.e., discrete analysis. The most important result found is that the best available option in any large‐scale decision‐making problem can be configured as an attractor, in a distributed and timely manner. We suggest that the proposed model has the potential to facilitate decision‐making processes in large‐scale settings. © 2005 Wiley Periodicals, Inc. Complexity 11:28–38, 2005 相似文献
50.
Anatoliy Samoilenko Manuel Pinto Sergei Trofimchuk 《Proceedings of the American Mathematical Society》2005,133(1):145-154
We apply the Krylov and Bogolyubov asymptotic integration procedure to asymptotically autonomous systems. First, we consider linear systems with quasi-periodic coefficient matrix multiplied by a scalar factor vanishing at infinity. Next, we study the asymptotically autonomous Van-der-Pol oscillator.