全文获取类型
收费全文 | 1797篇 |
免费 | 82篇 |
国内免费 | 134篇 |
专业分类
化学 | 198篇 |
力学 | 76篇 |
综合类 | 16篇 |
数学 | 1425篇 |
物理学 | 298篇 |
出版年
2023年 | 13篇 |
2022年 | 43篇 |
2021年 | 36篇 |
2020年 | 42篇 |
2019年 | 43篇 |
2018年 | 35篇 |
2017年 | 39篇 |
2016年 | 50篇 |
2015年 | 39篇 |
2014年 | 78篇 |
2013年 | 151篇 |
2012年 | 63篇 |
2011年 | 87篇 |
2010年 | 71篇 |
2009年 | 117篇 |
2008年 | 115篇 |
2007年 | 125篇 |
2006年 | 103篇 |
2005年 | 80篇 |
2004年 | 83篇 |
2003年 | 52篇 |
2002年 | 65篇 |
2001年 | 52篇 |
2000年 | 42篇 |
1999年 | 54篇 |
1998年 | 33篇 |
1997年 | 35篇 |
1996年 | 31篇 |
1995年 | 23篇 |
1994年 | 27篇 |
1993年 | 18篇 |
1992年 | 17篇 |
1991年 | 15篇 |
1990年 | 6篇 |
1989年 | 15篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 11篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1974年 | 3篇 |
1973年 | 7篇 |
排序方式: 共有2013条查询结果,搜索用时 15 毫秒
141.
条件Erlang分布的双参数加法定理 总被引:2,自引:0,他引:2
X(γ)和Y(k)服从参数(γ,λ)和(k,μ)的Erlang分布且相互独立.本文证明了在X(γ)相似文献
142.
Barahona and Mahjoub found a defining system of the stable set polytope for a graph with a cut-set of cardinality 2. We extend this result to cut-sets composed of a complete graph minus an edge and use the new theorem to derive a class of facets. 相似文献
143.
AnInequalityofMatrixandBayesUnbiasedEstimatesZhangYaoting(ShanghaiUniversityofFinanceandEconomics,200433)AbstractTheinequali... 相似文献
144.
On the Block Independence in G-Inverse and Reflexive Inner Inverse of A Partitioned Matrix 总被引:1,自引:0,他引:1
Yong Hui LIU Mu Sheng WEI 《数学学报(英文版)》2007,23(4):723-730
By applying the multiple quotient singular value decomposition QQQQQ-SVD, we study the block independence in g-inverse and reflexive inner inverse of 2× 2 partitioned matrices, and prove a conjecture in [Yiju Wang, SIAM J. Matrix Anal. Appl., 19(2), 407-415(1998)]. 相似文献
145.
John M. Myers 《Foundations of Physics》2006,36(7):1012-1035
Motivated by a recent proof of free choices in linking equations to the experiments they describe, I clarify some relations among purely mathematical entities featured in quantum mechanics (probabilities, density operators, partial traces, and operator-valued measures), thereby allowing applications of these entities to the modeling of a wider variety of physical situations. I relate conditional probabilities associated with projection-valued measures to conditional density operators identical, in some cases but not in others, to the usual reduced density operators. While a fatal obstacle precludes associating conditional density operators with general non-projective measures, tensor products of general positive operator-valued measures (POVMs) are associated with conditional density operators. This association together with the free choice of probe particles allows a postulate of state reductions to be replaced by a theorem. An application shows an equivalence between one form of quantum key distribution and another with respect to certain eavesdropping attacks. 相似文献
146.
Emilio Santos has argued (Santos, Studies in History and Philosophy of Physics http: //arxiv-org/abs/quant-ph/0410193) that to date, no experiment has provided a loophole-free refutation of Bell’s inequalities. He believes that this provides strong evidence for the principle of local realism, and argues that we should reject this principle only if we have extremely strong evidence. However, recent work by Malley and Fine (Non-commuting observables and local realism, http: //arxiv-org/abs/quant-ph/0505016) appears to suggest that experiments refuting Bell’s inequalities could at most confirm that quantum mechanical quantities do not commute. They also suggest that experiments performed on a single system could refute local realism. In this paper, we develop a connection between the work of Malley and Fine and an argument by Bub from some years ago [Bub, The Interpretation of Quantum Mechanics, Chapter VI(Reidel, Dodrecht,1974)]. We also argue that the appearance of conflict between Santos on the one hand and Malley and Fine on the other is a result of differences in the way they understand local realism. 相似文献
147.
要解决的问题是一个矩阵是否可以分解为若干稳定 (连续时间意义下 )矩阵的和 .通过推广Ito,Hattori and Maeda在文献 [2 ]中使用的方法并运用其中的成果 ,我们得到了更为准确的相关结论 . 相似文献
148.
Andreas Weiermann 《Mathematical Logic Quarterly》2007,53(1):4-18
We classify the phase transition thresholds from provability to unprovability for certain Friedman-style miniaturizations of Kruskal's Theorem and Higman's Lemma. In addition we prove a new and unexpected phase transition result for ε0. Motivated by renormalization and universality issues from statistical physics we finally state a universality hypothesis. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
149.
It is shown that a Gaussian measure in a given infinite-dimensional Banach space always admits an essentially unique Gaussian disintegration with respect to a given continuous linear operator. This covers a similar statement made earlier in [Lee and Wasilkowski, Approximation of linear functionals on a Banach space with a Gaussian measure, J. Complexity 2(1) (1986) 12–43.] for the case of finite-rank operators. 相似文献
150.
Spatial Nonparametric Regression Estimation: Non-isotropic Case 总被引:3,自引:0,他引:3
Zu-di Lu Xing ChenInstitute of Systems Science Academy of Mathematics Systems Sciences Chinese Academy of Sciences. Beijing ChinaDepartment of Statistics Yunnan University Kunming China 《应用数学学报(英文版)》2002,18(4):641-656
Data collected on the surface of the earth often has spatial interaction. In this paper, a non-isotropic mixing spatial data process is introduced, and under such a spatial structure a nonparametric kernel method is suggested to estimate a spatial conditional regression. Under mild regularities, sufficient conditions are derived to ensure the weak consistency as well as the convergence rates for the kernel estimator. Of interest are the following: (1) All the conditions imposed on the mixing coefficient and the bandwidth are simple; (2) Differently from the time series setting, the bandwidth is found to be dependent on the dimension of the site in space as well; (3) For weak consistency, the mixing coefficient is allowed to be unsummable and the tendency of sample size to infinity may be in different manners along different direction in space; (4) However, to have an optimal convergence rate, faster decreasing rates of mixing coefficient and the tendency of sample size to infinity along each direction a 相似文献