全文获取类型
收费全文 | 5583篇 |
免费 | 202篇 |
国内免费 | 22篇 |
专业分类
化学 | 3912篇 |
晶体学 | 49篇 |
力学 | 140篇 |
数学 | 756篇 |
物理学 | 950篇 |
出版年
2023年 | 39篇 |
2022年 | 32篇 |
2021年 | 118篇 |
2020年 | 93篇 |
2019年 | 89篇 |
2018年 | 81篇 |
2017年 | 86篇 |
2016年 | 207篇 |
2015年 | 147篇 |
2014年 | 162篇 |
2013年 | 350篇 |
2012年 | 422篇 |
2011年 | 455篇 |
2010年 | 264篇 |
2009年 | 233篇 |
2008年 | 389篇 |
2007年 | 384篇 |
2006年 | 309篇 |
2005年 | 342篇 |
2004年 | 257篇 |
2003年 | 216篇 |
2002年 | 175篇 |
2001年 | 79篇 |
2000年 | 85篇 |
1999年 | 48篇 |
1998年 | 46篇 |
1997年 | 43篇 |
1996年 | 74篇 |
1995年 | 39篇 |
1994年 | 35篇 |
1993年 | 50篇 |
1992年 | 38篇 |
1991年 | 43篇 |
1990年 | 49篇 |
1989年 | 35篇 |
1988年 | 39篇 |
1987年 | 40篇 |
1986年 | 24篇 |
1985年 | 36篇 |
1984年 | 23篇 |
1983年 | 16篇 |
1982年 | 19篇 |
1981年 | 16篇 |
1980年 | 14篇 |
1979年 | 16篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1976年 | 4篇 |
1974年 | 9篇 |
1972年 | 3篇 |
排序方式: 共有5807条查询结果,搜索用时 31 毫秒
1.
Ramos Fernando Flores Henoc Camarillo E. Adriana Ledo J. Manuel 《Structural chemistry》2022,33(2):379-388
Structural Chemistry - In the present work, the energy contribution of the sulfur atom in a heterocycle and in a disulfide bond in solid and gas phases was calculated. To achieve this goal,... 相似文献
2.
Russian Physics Journal - Aiming at problems of low probability of interception and poor anti-jamming performance of the multi-output radar, the numerical simulation based on a chaos optimization... 相似文献
3.
Ribeiro Sabrina Dias Meneguin Andria Bagliotti Barud Hernane da Silva Silva Jhonatan Miguel Oliveira Rafael L. Asuno Rosana Maria Nascimento de Tormin Thiago Faria Muoz Rodrigo Alejandro Abarza Filho Guimes Rodrigues Ribeiro Clovis Augusto 《Journal of Thermal Analysis and Calorimetry》2022,147(13):7265-7275
Journal of Thermal Analysis and Calorimetry - Cellophane film production generates cellulosic residues from scraps, edges, and low-quality films. In this work, cellophane was used as a raw material... 相似文献
4.
5.
AbstractWe study the inverse problem of parameter identification in noncoercive variational problems that commonly appear in applied models. We examine the differentiability of the set-valued parameter-to-solution map using the first-order and the second-order contingent derivatives. We explore the inverse problem using the output least-squares and the modified output least-squares objectives. By regularizing the noncoercive variational problem, we obtain a single-valued regularized parameter-to-solution map and investigate its smoothness and boundedness. We also consider optimization problems using the output least-squares and the modified output least-squares objectives for the regularized variational problem. We give a complete convergence analysis showing that for the output least-squares and the modified output least-squares, the regularized minimization problems approximate the original optimization problems suitably. We also provide the first-order and the second-order adjoint method for the computation of the first-order and the second-order derivatives of the output least-squares objective. We provide discrete formulas for the gradient and the Hessian calculation and present numerical results. 相似文献
6.
Yorioka introduced a class of ideals (parametrized by reals) on the Cantor space to prove that the relation between the size of the continuum and the cofinality of the strong measure zero ideal on the real line cannot be decided in . We construct a matrix iteration of c.c.c. posets to force that, for many ideals in that class, their associated cardinal invariants (i.e., additivity, covering, uniformity and cofinality) are pairwise different. In addition, we show that, consistently, the additivity and cofinality of Yorioka ideals does not coincide with the additivity and cofinality (respectively) of the ideal of Lebesgue measure zero subsets of the real line. 相似文献
7.
Prof. Miguel A. Sierra Prof. Luis Casarrubios Dr. María C. de la Torre 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(30):7232-7242
Overuse and misuse of antibacterial drugs has resulted in bacteria resistance and in an increase in mortality rates due to bacterial infections. Therefore, there is an imperative necessity of new antibacterial drugs. Bio-organometallic derivatives of antibacterial agents offer an opportunity to discover new active antibacterial drugs. These compounds are well-characterized products and, in several examples, their antibacterial activities have been studied. Both inhibition of the antibacterial activity and strong increase in the antibiotic activity of the parent drug have been found. The synthesis of the main classes of bio-organometallic derivatives of these drugs, as well as examples of the use of structure–activity relation (SAR) studies to increase the activity and to understand the mode of action of bio-organometallic antimicrobial peptides (BOAMPs) and platensimicyn bio-organometallic mimics is presented in this article. 相似文献
8.
9.
Miguel Ballesteros Dirk-André Deckert Felix Hänle 《Journal of Functional Analysis》2019,276(8):2524-2581
We extend the method of Pizzo multiscale analysis for resonances introduced in [5] in order to infer analytic properties of resonances and eigenvalues (and their eigenprojections) as well as estimates for the localization of the spectrum of dilated Hamiltonians and norm-bounds for the corresponding resolvent operators, in neighborhoods of resonances and eigenvalues. We apply our method to the massless Spin–Boson model assuming a slight infrared regularization. We prove that the resonance and the ground-state eigenvalue (and their eigenprojections) are analytic with respect to the dilation parameter and the coupling constant. Moreover, we prove that the spectrum of the dilated Spin–Boson Hamiltonian in the neighborhood of the resonance and the ground-state eigenvalue is localized in two cones in the complex plane with vertices at the location of the resonance and the ground-state eigenvalue, respectively. Additionally, we provide norm-estimates for the resolvent of the dilated Spin–Boson Hamiltonian near the resonance and the ground-state eigenvalue. The topic of analyticity of eigenvalues and resonances has let to several studies and advances in the past. However, to the best of our knowledge, this is the first time that it is addressed from the perspective of Pizzo multiscale analysis. Once the multiscale analysis is set up our method gives easy access to analyticity: Essentially, it amounts to proving it for isolated eigenvalues only and use that uniform limits of analytic functions are analytic. The type of spectral and resolvent estimates that we prove are needed to control the time evolution including the scattering regime. The latter will be demonstrated in a forthcoming publication. The introduced multiscale method to study spectral and resolvent estimates follows its own inductive scheme and is independent (and different) from the method we apply to construct resonances. 相似文献
10.
Nonlinear Dynamics - Delay-coordinate maps have been widely used recently to study nonlinear dynamical systems, where there is only access to the time series of one of their variables. Here, we... 相似文献