全文获取类型
收费全文 | 6154篇 |
免费 | 792篇 |
国内免费 | 557篇 |
专业分类
化学 | 1699篇 |
晶体学 | 44篇 |
力学 | 717篇 |
综合类 | 87篇 |
数学 | 1943篇 |
物理学 | 3013篇 |
出版年
2024年 | 22篇 |
2023年 | 70篇 |
2022年 | 192篇 |
2021年 | 177篇 |
2020年 | 207篇 |
2019年 | 185篇 |
2018年 | 156篇 |
2017年 | 182篇 |
2016年 | 236篇 |
2015年 | 175篇 |
2014年 | 289篇 |
2013年 | 496篇 |
2012年 | 311篇 |
2011年 | 421篇 |
2010年 | 301篇 |
2009年 | 333篇 |
2008年 | 359篇 |
2007年 | 412篇 |
2006年 | 307篇 |
2005年 | 292篇 |
2004年 | 260篇 |
2003年 | 265篇 |
2002年 | 251篇 |
2001年 | 218篇 |
2000年 | 206篇 |
1999年 | 154篇 |
1998年 | 155篇 |
1997年 | 125篇 |
1996年 | 112篇 |
1995年 | 88篇 |
1994年 | 85篇 |
1993年 | 67篇 |
1992年 | 60篇 |
1991年 | 53篇 |
1990年 | 36篇 |
1989年 | 39篇 |
1988年 | 26篇 |
1987年 | 25篇 |
1986年 | 19篇 |
1985年 | 16篇 |
1984年 | 19篇 |
1983年 | 12篇 |
1982年 | 21篇 |
1981年 | 14篇 |
1980年 | 7篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 6篇 |
1974年 | 6篇 |
排序方式: 共有7503条查询结果,搜索用时 0 毫秒
11.
Linear and nonlinear optical properties of racemic (±)2-(α-methylbenzylamino)-5-nitropyridine ((±)MBANP) single crystals have been comprehensively investigated and compared with those of the enantiomorph (–)2-(α-methylbenzylamino)-5-nitropyridine ((–)MBANP) crystals. (±)MBANP crystal exhibits very high chemical and physical stability, but relatively small nonlinear optical coefficients (d31 = 6.8 pm/V, d32 = 4.7 pm/V, d33 = 0.84 pm/V). A comparison between the nonlinear optical coefficients of (±)MBANP and (–)MBANP demonstrates the validity of the oriented-gas model in molecular crystals that neglects all the contributions from intermolecular interaction. 相似文献
12.
Djamel Meraghni Abdelhakim Necir 《Methodology and Computing in Applied Probability》2007,9(4):557-572
The characteristic exponent α of a Lévy-stable law S
α
(σ, β, μ) was thoroughly studied as the extreme value index of a heavy tailed distribution. For 1 < α < 2, Peng (Statist. Probab. Lett. 52: 255–264, 2001) has proposed, via the extreme value approach, an asymptotically normal estimator for the location parameter μ. In this paper, we derive by the same approach, an estimator for the scale parameter σ and we discuss its limiting behavior.
相似文献
13.
In this note, we study convergence rates in the law of large numbers for independent and identically distributed random variables under sublinear expectations. We obtain a strong L^p-convergence version and a strongly quasi sure convergence version of the law of large numbers. 相似文献
14.
Youssef Randjiou 《Journal of Theoretical Probability》2006,19(3):701-720
Let μ+(t) and μ−(t) be the locations of the maximum and minimum, respectively, of a standard Brownian motion in the interval [0,t]. We establish a joint integral test for the lower functions of μ+(t) and μ−(t), in the sense of Paul Lévy. In particular, it yields the law of the iterated logarithm for max(μ+(t),μ−(t)) as a straightforward consequence. Our result is in agreement with well-known theorems of Chung and Erdős [(1952) Trans. Amer. Math. Soc. 72, 179–186.], and Csáki, F?ldes and Révész [(1987) Prob. Theory Relat. Fields
76, 477–497].
相似文献
15.
可交换随机变量序列的随机极限定理 总被引:1,自引:0,他引:1
本文讨论了可交换随机变量序列{Xn:n≥1}的极限定理,得到了可交换随机变量序列的随机强大数律及加权和定理,并推广了文[4]中的结果. 相似文献
16.
The periodic precipitation pattern formation in gelatinous media is interpreted as a moving boundary problem. The time law,
spacing law and width law are revisited on the basis of the new scenario. The explicit dependence of the geometric structure
on the initial concentrations of the reactants is derived. Matalon—Packter law, which relates the spacing coefficient with
the initial concentrations is reformulated removing many ambiguities and impractical parameters. Experimental results are
discussed to establish the significance of moving boundary concept in the diffusion controlled pattern forming systems 相似文献
17.
V. P. Maslov 《Theoretical and Mathematical Physics》2007,150(1):102-122
From the standpoint of thermodynamic averaging of fission microprocesses, we investigate the origin of radioactive release
in an NPP after an accident or after resource depletion. The genesis of the NPP release is interpreted as a new thermodynamic
phenomenon, a zeroth-order phase transition. This problem setting results in a problem in probabilistic number theory. We
prove the corresponding theorem leading to quantization of the Zipf law for the frequency of a zeroth-order phase transition
with different values of the jump of the Gibbs thermodynamic potential. We introduce the notion of hole dimension.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 150, No. 1, pp. 118–142, January, 2007. 相似文献
18.
Eric Flauraud Frdric Nataf Isabelle Faille Roland Masson 《Comptes Rendus Mecanique》2003,331(12):849-855
We present in this paper a domain decomposition method to treat faults in geological basin modeling. The particularity of this model is that the faults whose widths are very small in comparison with the basin size, are not characterized as subdomains any more but as interfaces between sedimentary blocks. The originality of this work lies in the formulation of this new fault model and in the definition and the computation of the interface conditions between the subdomains. To cite this article: E. Flauraud et al., C. R. Mecanique 331 (2003). 相似文献
19.
对数似然比与整值随机变量序列的一类强律 总被引:2,自引:0,他引:2
本文引进对数似然比作为整值随机变量序列相对于服从几何分布的独立随机变量序列的偏差的一种度量,并通过限制对数似然比给出了样本空间的一个子集.在此子集上得到了一类用不等式表示的强律,其中包含整值随机变量序列与相对熵密度及几何分布的熵函数有关的若干极限性质. 相似文献
20.
Tsuyoshi Katayama 《Queueing Systems》1992,11(3):299-306
This paper derives a conservation law for mean waiting times in a single-server multi-class service queueing system (M
X/G/1 type queue) with setup times which may be dependent on multiple customer classes and its arrival batch size by using the work decomposition property in the queueing system with vacations. 相似文献