全文获取类型
收费全文 | 115157篇 |
免费 | 8280篇 |
国内免费 | 9970篇 |
专业分类
化学 | 43816篇 |
晶体学 | 775篇 |
力学 | 10144篇 |
综合类 | 1689篇 |
数学 | 39322篇 |
物理学 | 37661篇 |
出版年
2024年 | 173篇 |
2023年 | 1022篇 |
2022年 | 2164篇 |
2021年 | 2270篇 |
2020年 | 2494篇 |
2019年 | 2703篇 |
2018年 | 2359篇 |
2017年 | 2728篇 |
2016年 | 3058篇 |
2015年 | 2624篇 |
2014年 | 4010篇 |
2013年 | 7618篇 |
2012年 | 4576篇 |
2011年 | 5231篇 |
2010年 | 4493篇 |
2009年 | 6360篇 |
2008年 | 7050篇 |
2007年 | 7540篇 |
2006年 | 6755篇 |
2005年 | 5695篇 |
2004年 | 5084篇 |
2003年 | 5251篇 |
2002年 | 5322篇 |
2001年 | 4160篇 |
2000年 | 3977篇 |
1999年 | 3543篇 |
1998年 | 3321篇 |
1997年 | 2528篇 |
1996年 | 2287篇 |
1995年 | 2017篇 |
1994年 | 1942篇 |
1993年 | 1567篇 |
1992年 | 1569篇 |
1991年 | 1169篇 |
1990年 | 1028篇 |
1989年 | 856篇 |
1988年 | 776篇 |
1987年 | 647篇 |
1986年 | 583篇 |
1985年 | 625篇 |
1984年 | 622篇 |
1983年 | 336篇 |
1982年 | 497篇 |
1981年 | 541篇 |
1980年 | 400篇 |
1979年 | 400篇 |
1978年 | 327篇 |
1977年 | 303篇 |
1976年 | 227篇 |
1973年 | 159篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
211.
一类拟线性大系统的稳定性 总被引:1,自引:0,他引:1
彭晓林 《新疆大学学报(理工版)》1991,8(1):41-45
本文应用大系统的分解方法和一个推广的不等式,研究了一类拟线性大系统的稳定性问题,所得结果简洁、易于验证,且推导过程不复杂,最后给出了应用实例。 相似文献
212.
Teruyuki Yorioka 《Mathematical Logic Quarterly》2006,52(2):203-216
We prove the iteration lemmata, which are the key lemmata to show that extensions by Pmax variations satisfy absoluteness for Π2-statements in the structure 〈H (ω 2), ∈, NSω 1, R 〉 for some set R of reals in L (ℝ), for the following statements: (1) The cofinality of the null ideal is ℵ1. (2) There exists a good basis of the strong measure zero ideal. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
213.
214.
The mechanism of X-ray waveguide-resonance propagation or the radiation superstream model, which can become the ground of X-ray nanophotonics, is discussed briefly. Some attention is devoted to features consideration of the simplest devices characterized by the waveguide-resonance transportation of X-ray beams. The experimental data showing the user possibilities of a simplest waveguide-resonators application for diffractometry are presented. We discuss the main reasons to improve the metrological characteristics for total reflection X-ray fluorescence (TXRF) analytical method in case when the target exciting beam is formed by a waveguide-resonator. Some problems appearing during the waveguide-resonator application are formulated. 相似文献
215.
This paper considers the general synchronization dynamics of coupled Van der Pol–Duffing oscillators. The linear and nonlinear stability analysis on the synchronization process is derived through the Whittaker method and the Floquet theory in addition to the multiple time scales method. A stability map displaying different dynamical states of the system is performed. Numerical simulation is carried out to support and to complement the accuracy of the analytical treatment. 相似文献
216.
Arthur W. Apter 《Mathematical Logic Quarterly》2006,52(5):457-463
We construct models for the level by level equivalence between strong compactness and supercompactness in which for κ the least supercompact cardinal and δ ≤ κ any cardinal which is either a strong cardinal or a measurable limit of strong cardinals, 2δ > δ + and δ is < 2δ supercompact. In these models, the structure of the class of supercompact cardinals can be arbitrary, and the size of the power set of κ can essentially be made as large as desired. This extends and generalizes [5, Theorem 2] and [4, Theorem 4]. We also sketch how our techniques can be used to establish a weak indestructibility result. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
217.
We study theoretically a nonlinear response of the planar metal/dielectric nanostructures constituted from periodical array
of ultra thin silver layers and the layers of Kerr-like nonlinear dielectric. We predict hysteresis-type dependences of the
components of the tensor of effective dielectric permittivity on the field intensity allowing the change in material transmission
properties from transparent to opaque and back at extremely low intensities of the light. It makes possible to control the
light by light in all-optical nanoscale devices and circuits. 相似文献
218.
G. K. Shenoy 《Hyperfine Interactions》2006,170(1-3):5-13
Stanley L. Ruby (1924–2004) made major contributions to Mössbauer spectroscopy and was the first to suggest the feasibility of observing the Mössbauer effect using synchrotron radiation. In this article we recall his scientific legacy that have inspired his scientific colleagues. 相似文献
219.
W. Kotarski 《Journal of Optimization Theory and Applications》1987,54(3):565-573
Combining the results of Walczak (Ref. 1) and Lasiecka (Refs. 2 and 3), we extend the well-known Dubovicki-Milutin theorem in two directions: (i) We allow for treatment of several equality constraints in optimization problems; and (ii) We assume less regularity of optimization problems by requiring the existence of external cones instead of tangent cones. An example of an optimization problem is also considered. 相似文献
220.
This article studies some geometrical aspects of the semidefinite linear complementarity problem (SDLCP), which can be viewed as a generalization of the well-known linear complementarity problem (LCP). SDLCP is a special case of a complementarity problem over a closed convex cone, where the cone considered is the closed convex cone of positive semidefinite matrices. It arises naturally in the unified formulation of a pair of primal-dual semidefinite programming problems. In this article, we introduce the notion of complementary cones in the semidefinite setting using the faces of the cone of positive semidefinite matrices and show that unlike complementary cones induced by an LCP, semidefinite complementary cones need not be closed. However, under R0-property of the linear transformation, closedness of all the semidefinite complementary cones induced by L is ensured. We also introduce the notion of a principal subtransformation with respect to a face of the cone of positive semidefinite matrices and show that for a self-adjoint linear transformation, strict copositivity is equivalent to strict semimonotonicity of each principal subtransformation. Besides the above, various other solution properties of SDLCP will be interpreted and studied geometrically. 相似文献