全文获取类型
收费全文 | 21277篇 |
免费 | 2981篇 |
国内免费 | 2143篇 |
专业分类
化学 | 2231篇 |
晶体学 | 30篇 |
力学 | 1813篇 |
综合类 | 542篇 |
数学 | 14740篇 |
物理学 | 7045篇 |
出版年
2024年 | 25篇 |
2023年 | 181篇 |
2022年 | 287篇 |
2021年 | 385篇 |
2020年 | 452篇 |
2019年 | 461篇 |
2018年 | 478篇 |
2017年 | 617篇 |
2016年 | 704篇 |
2015年 | 545篇 |
2014年 | 1100篇 |
2013年 | 1434篇 |
2012年 | 1195篇 |
2011年 | 1404篇 |
2010年 | 1272篇 |
2009年 | 1502篇 |
2008年 | 1535篇 |
2007年 | 1588篇 |
2006年 | 1407篇 |
2005年 | 1346篇 |
2004年 | 1085篇 |
2003年 | 988篇 |
2002年 | 828篇 |
2001年 | 777篇 |
2000年 | 703篇 |
1999年 | 616篇 |
1998年 | 551篇 |
1997年 | 515篇 |
1996年 | 363篇 |
1995年 | 299篇 |
1994年 | 247篇 |
1993年 | 186篇 |
1992年 | 161篇 |
1991年 | 134篇 |
1990年 | 139篇 |
1989年 | 96篇 |
1988年 | 88篇 |
1987年 | 81篇 |
1986年 | 70篇 |
1985年 | 82篇 |
1984年 | 66篇 |
1983年 | 47篇 |
1982年 | 63篇 |
1981年 | 59篇 |
1980年 | 38篇 |
1979年 | 34篇 |
1978年 | 30篇 |
1977年 | 26篇 |
1976年 | 30篇 |
1973年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
本文用凸函数的方法研究了概率测度的矩母函数和由C.J.Stone提出的拟对称性,并刻画了Martin边界的法向量.拟对称性在随机游动的比例极限定理中是一个重要的概念.这些结果可应用于Levy过程的研究. 相似文献
132.
A Bayesian approach is used to analyze the seismic events with magnitudes at least 4.7 on Taiwan. Following the idea proposed
by Ogata (1988,Journal of the American Statistical Association,83, 9–27), an epidemic model for the process of occurrence times given the observed magnitude values is considered, incorporated
with gamma prior distributions for the parameters in the model, while the hyper-parameters of the prior are essentially determined
by the seismic data in an earlier period. Bayesian inference is made on the conditional intensity function via Markov chain
Monte Carlo method. The results yield acceptable accuracies in predicting large earthquake events within short time periods. 相似文献
133.
134.
We prove equivalence of the definitions by the author and by Korevaar and Schoen of the Sobolev classes of mappings of a domain of an arithmetic n-dimensional space to a metric space. 相似文献
135.
Pearson-χ~2距离的若干性质 总被引:18,自引:0,他引:18
李开灿 《数学的实践与认识》2003,33(1):49-53
本文对数理统计中常用的 Pearson- χ2距离的分析特性进行了讨论 ,得到了这一距离的一些解析性质 ,最后我们还给出了几个常用距离的关系 . 相似文献
136.
137.
We consider some types of packet discretization for continuous spectra in quantum scattering problems. As we previously showed, this discretization leads to a convenient finite-dimensional (i.e., matrix) approximation for integral operators in the scattering theory and allows reducing the solution of singular integral equations connected with the scattering theory to some suitable purely algebraic equations on an analytic basis. All singularities are explicitly singled out. Our primary emphasis is on realizing the method practically. 相似文献
138.
Patrizio Frosini 《Geometriae Dedicata》2004,108(1):105-110
In this paper we prove that for every real-valued Morse function φ on a smooth closed manifold ℳ and every neighborhood U of its critical points a suitable Riemannian metric μ
U
exists such that φ is linear outside
U 相似文献
139.
TieYong YangGuangjun 《分析论及其应用》2004,20(1):58-68
In this paper, we construct some continuous but non-differentiable functions defined by quinary decimal, that are Kiesswetter-like functions. We discuss their properties, then investigate the Hausdorff dimensions of graphs of these functions and give a detailed proof. 相似文献
140.
Werner Kaller 《Journal of Quantitative Spectroscopy & Radiative Transfer》2004,87(2):107-117
The angular dependence of light scattered by aerosol particles in the atmosphere—the aerosol phase function—is one of the key properties of every radiative transfer and climate model. Side-scattering in the atmosphere is currently believed to be underestimated by most of the radiative transfer models in certain cases. The aerosol phase function can be measured with polar nephelometers.An innovative polar nephelometer able to measure the phase function of ambient aerosol directly is presented in this publication. The performance of the device was simulated completely using ray-tracing techniques. The results of these simulations are used to interpret the measurement data precisely. The measurements with the new polar nephelometer are fully automated. The quality of the measurement results was verified using different approaches. The values of the statistical and systematic error in measuring atmospheric aerosol are about 4% each. Scattering angles from 10° to 160° were measured and it is shown that with the same design this range can be extended to 3-177° in steps of 0.16° with an aperture of less than 1.8°.Measurements of the aerosol phase function are presented and compared with data taken with an integrating nephelometer and measurements of the particulate matter concentration. All data correlate very well. The described polar nephelometer can measure the phase function and the scattering coefficient of atmospheric aerosol with high accuracy and can be used for continuous monitoring measurements as well as in field campaigns. 相似文献