全文获取类型
收费全文 | 10544篇 |
免费 | 827篇 |
国内免费 | 1030篇 |
专业分类
化学 | 4994篇 |
晶体学 | 48篇 |
力学 | 453篇 |
综合类 | 101篇 |
数学 | 4469篇 |
物理学 | 2336篇 |
出版年
2024年 | 12篇 |
2023年 | 112篇 |
2022年 | 106篇 |
2021年 | 139篇 |
2020年 | 210篇 |
2019年 | 239篇 |
2018年 | 229篇 |
2017年 | 286篇 |
2016年 | 270篇 |
2015年 | 283篇 |
2014年 | 465篇 |
2013年 | 1321篇 |
2012年 | 566篇 |
2011年 | 555篇 |
2010年 | 470篇 |
2009年 | 590篇 |
2008年 | 604篇 |
2007年 | 699篇 |
2006年 | 533篇 |
2005年 | 464篇 |
2004年 | 454篇 |
2003年 | 414篇 |
2002年 | 1017篇 |
2001年 | 273篇 |
2000年 | 309篇 |
1999年 | 237篇 |
1998年 | 260篇 |
1997年 | 169篇 |
1996年 | 183篇 |
1995年 | 157篇 |
1994年 | 128篇 |
1993年 | 118篇 |
1992年 | 85篇 |
1991年 | 68篇 |
1990年 | 66篇 |
1989年 | 67篇 |
1988年 | 49篇 |
1987年 | 29篇 |
1986年 | 32篇 |
1985年 | 19篇 |
1984年 | 25篇 |
1983年 | 7篇 |
1982年 | 14篇 |
1981年 | 12篇 |
1980年 | 8篇 |
1979年 | 14篇 |
1978年 | 9篇 |
1977年 | 6篇 |
1976年 | 6篇 |
1973年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Mauno Rnkk 《Nonlinear Analysis: Hybrid Systems》2007,1(4):560-576
In this paper, we discuss modelling and analysis of hybrid systems with physical interaction dynamics. Such systems are typically considered complex and they are modelled using abstractions. Abstractions may, however, unintentionally exclude critical details, leading to partial or false results. Therefore, we study here use of a particle system in modelling and analysis. The novelty of the particle system is that it is designed to reveal interaction dynamics as emergent dynamics; thus, supporting analysis of complex and intricate interaction dynamics with acceptable modelling effort. As the main contribution, we formalize the particle system, and use it to model and analyze hybrid systems, both mechanical and biological, with nontrivial interaction dynamics. 相似文献
92.
本文得到复流形局部q-凸楔形上(r,s)型微分形式的带权的同伦公式和(r,s)型的方程的带权的连续解,并给出(r,s)型微分形式的不含边界积分的新的带权的同伦公式和(r,s)型的方程的新的带权的连续解.这些新的带权公式尤其适用于具有非光滑边界的局部q-凸楔形,这时不但可以避免边界积分的复杂估计,而且积分密度也不必在边界有定义,只要在区域上有定义就行.其次,引进权因子,带权的积分公式在应用上(比如在函数的插值方面)具有更大的灵活性. 相似文献
93.
Three different analytical solutions are presented for a potential vortex ring using three different streamfunctions. Verification studies confirm that all three approaches are valid. It is found that the solution obtained using the Biot–Savart law is the most efficient method due to its simplicity. It is shown that all analytical results are accurate to within machine accuracy and sample calculations are included. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
94.
The existing model for multivariate skew normal data does not cohere with the joint distribution of a random sample from a
univariate skew normal distribution. This incoherence causes awkward interpretation for data analysis in practice, especially
in the development of the sampling distribution theory. In this paper, we propose a refined model that is coherent with the
joint distribution of the univariate skew normal random sample, for multivariate skew normal data. The proposed model extends
and strengthens the multivariate skew model described in Azzalini (1985,Scandinavian Journal of Statistics,12, 171–178). We present a stochastic representation for the newly proposed model, and discuss a bivariate setting, which confirms
that the newly proposed model is more plausible than the one given by Azzalini and Dalla Valle (1996,Biometrika,83, 715–726). 相似文献
95.
设G是有限群,|G|-1∈R.本文证明了与强G-分次环R,R#k[G]*,非分次R-模和Re-模有关的两个Maschke-型定理. 相似文献
96.
Michael Szydlo 《Journal of Number Theory》2004,104(1):75-99
Kodaira and Néron classified and described the geometry of the special fibers of the Néron model of an elliptic curve defined over a discrete valuation ring with a perfect residue field. Tate described an algorithm to determine the special fiber type by manipulating the Weierstrass equation. In the case of non-perfect residue fields, we discover new fiber types which are not on the Kodaira-Néron list. We describe these new types and extend Tate's algorithm to deal with all discrete valuation rings. Specifically, we show how to translate a Weierstrass equation into a form where the reduction type may be easily determined. Having determined the special fiber type, we construct the regular model of the curve with explicit blow-up calculations. We also provide tables that serve as a simple reference for the algorithm and which succinctly summarize the results. 相似文献
97.
98.
Jeremy Lovejoy 《Journal of Number Theory》2004,106(1):178-186
It is shown that counting certain differences of overpartition functions is equivalent to counting elements of a given norm in appropriate real quadratic fields. 相似文献
99.
Naoki Murabayashi 《Journal of Number Theory》2004,108(2):268-286
The purpose of this paper is to decide the conditions under which a CM elliptic curve is modular over its field of definition. 相似文献
100.
We consider an extension of the Feynman path integral to the quantum mechanics of noncommuting spatial coordinates and formulate the corresponding formalism for noncommutative classical dynamics related to quadratic Lagrangians (Hamiltonians). The basis of our approach is that a quantum mechanical system with a noncommutative configuration space can be regarded as another effective system with commuting spatial coordinates. Because the path integral for quadratic Lagrangians is exactly solvable and a general formula for the probability amplitude exists, we restrict our research to this class of Lagrangians. We find a general relation between quadratic Lagrangians in their commutative and noncommutative regimes and present the corresponding noncommutative path integral. This method is illustrated with two quantum mechanical systems in the noncommutative plane: a particle in a constant field and a harmonic oscillator. 相似文献