全文获取类型
收费全文 | 17366篇 |
免费 | 2240篇 |
国内免费 | 1108篇 |
专业分类
化学 | 923篇 |
晶体学 | 18篇 |
力学 | 578篇 |
综合类 | 273篇 |
数学 | 2710篇 |
物理学 | 4345篇 |
无线电 | 11867篇 |
出版年
2024年 | 73篇 |
2023年 | 215篇 |
2022年 | 419篇 |
2021年 | 605篇 |
2020年 | 514篇 |
2019年 | 372篇 |
2018年 | 379篇 |
2017年 | 585篇 |
2016年 | 676篇 |
2015年 | 833篇 |
2014年 | 1339篇 |
2013年 | 1256篇 |
2012年 | 1212篇 |
2011年 | 1208篇 |
2010年 | 925篇 |
2009年 | 1023篇 |
2008年 | 1247篇 |
2007年 | 1259篇 |
2006年 | 1003篇 |
2005年 | 885篇 |
2004年 | 779篇 |
2003年 | 703篇 |
2002年 | 564篇 |
2001年 | 425篇 |
2000年 | 373篇 |
1999年 | 331篇 |
1998年 | 262篇 |
1997年 | 263篇 |
1996年 | 194篇 |
1995年 | 165篇 |
1994年 | 120篇 |
1993年 | 108篇 |
1992年 | 82篇 |
1991年 | 67篇 |
1990年 | 55篇 |
1989年 | 41篇 |
1988年 | 33篇 |
1987年 | 24篇 |
1986年 | 18篇 |
1985年 | 18篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1982年 | 3篇 |
1981年 | 12篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1977年 | 3篇 |
1974年 | 2篇 |
1959年 | 6篇 |
1936年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
161.
162.
Ioannis K. Argyros 《Journal of Mathematical Analysis and Applications》2004,298(2):374-397
We provide a local as well as a semilocal convergence analysis for two-point Newton-like methods in a Banach space setting under very general Lipschitz type conditions. Our equation contains a Fréchet differentiable operator F and another operator G whose differentiability is not assumed. Using more precise majorizing sequences than before we provide sufficient convergence conditions for Newton-like methods to a locally unique solution of equation F(x)+G(x)=0. In the semilocal case we show under weaker conditions that our error estimates on the distances involved are finer and the information on the location of the solution at least as precise as in earlier results. In the local case a larger radius of convergence is obtained. Several numerical examples are provided to show that our results compare favorably with earlier ones. As a special case we show that the famous Newton-Kantorovich hypothesis is weakened under the same hypotheses as the ones contained in the Newton-Kantorovich theorem. 相似文献
163.
In this paper, we continue the analysis of the image regularity condition (IRC) as introduced in a previous paper where we have proved that IRC implies the existence of generalized Lagrange-John multipliers with first component equal to 1. The term generalized is connected with the fact that the separation (in the image space) is not necessarily linear (when we have classic Lagrange-John multipliers), but it can be also nonlinear. Here, we prove that the IRC guarantees, also in the nondifferentiable case, the fact that 0 is a solution of the first-order homogeneized (linearized) problem obtained by means of the Dini-Hadamard derivatives. 相似文献
164.
165.
该文给出赋0rlicz范数的Musielak-Orlicz序列空间中Gateaux可微点(光滑点)与Frechet可微点(强光滑点)的判定准则.在此基础上推出了该空间具有光滑性或强光滑性的充分必要条件. 相似文献
166.
一种固定阈值的毫米波图像边缘检测方法 总被引:1,自引:0,他引:1
文章提出了一种固定阈值的毫米波图像边缘检测方法。根据图像的统计特征确定出像素的标准梯度强度,并采用单阈值对图像进行边缘粗定位,然后施行非最大抑制处理和滤波,得到最终检测结果。由于该算法对各幅毫米波图像设置相同的阈值,故能实现自动检测,同时还具有计算量小的特点。实验结果表明该方法进行毫米波图像边缘检测的有效性和可行性。 相似文献
167.
168.
169.
Keith Jonathan M. Kroese Dirk P. Bryant Darryn 《Methodology and Computing in Applied Probability》2004,6(1):29-53
A recent development of the Markov chain Monte Carlo (MCMC) technique is the emergence of MCMC samplers that allow transitions between different models. Such samplers make possible a range of computational tasks involving models, including model selection, model evaluation, model averaging and hypothesis testing. An example of this type of sampler is the reversible jump MCMC sampler, which is a generalization of the Metropolis–Hastings algorithm. Here, we present a new MCMC sampler of this type. The new sampler is a generalization of the Gibbs sampler, but somewhat surprisingly, it also turns out to encompass as particular cases all of the well-known MCMC samplers, including those of Metropolis, Barker, and Hastings. Moreover, the new sampler generalizes the reversible jump MCMC. It therefore appears to be a very general framework for MCMC sampling. This paper describes the new sampler and illustrates its use in three applications in Computational Biology, specifically determination of consensus sequences, phylogenetic inference and delineation of isochores via multiple change-point analysis. 相似文献
170.
研究了Banach空间中拟-似变分包含解的存在与逼近问题.给出了一种寻求解的新的迭代算法,建立了具混合误差的Ishikawa型迭代序列强收敛到解的充要条件.所得结果推广了一些相关的结果. 相似文献