全文获取类型
收费全文 | 103612篇 |
免费 | 1050篇 |
国内免费 | 484篇 |
专业分类
化学 | 39183篇 |
晶体学 | 956篇 |
力学 | 7471篇 |
综合类 | 9篇 |
数学 | 35319篇 |
物理学 | 22208篇 |
出版年
2022年 | 132篇 |
2021年 | 385篇 |
2020年 | 399篇 |
2019年 | 370篇 |
2018年 | 10735篇 |
2017年 | 10497篇 |
2016年 | 6684篇 |
2015年 | 1446篇 |
2014年 | 974篇 |
2013年 | 1425篇 |
2012年 | 5152篇 |
2011年 | 11959篇 |
2010年 | 6437篇 |
2009年 | 6833篇 |
2008年 | 7873篇 |
2007年 | 9965篇 |
2006年 | 1451篇 |
2005年 | 2926篇 |
2004年 | 3159篇 |
2003年 | 3123篇 |
2002年 | 1756篇 |
2001年 | 809篇 |
2000年 | 809篇 |
1999年 | 475篇 |
1998年 | 472篇 |
1997年 | 431篇 |
1996年 | 555篇 |
1995年 | 449篇 |
1994年 | 400篇 |
1993年 | 437篇 |
1992年 | 387篇 |
1991年 | 339篇 |
1990年 | 283篇 |
1989年 | 277篇 |
1988年 | 248篇 |
1987年 | 244篇 |
1986年 | 249篇 |
1985年 | 286篇 |
1984年 | 263篇 |
1983年 | 232篇 |
1982年 | 239篇 |
1981年 | 224篇 |
1980年 | 227篇 |
1979年 | 205篇 |
1978年 | 218篇 |
1977年 | 168篇 |
1976年 | 158篇 |
1975年 | 135篇 |
1974年 | 151篇 |
1973年 | 150篇 |
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
1.
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
2.
de Oliveira Fabiana R. Oliveira Fabrícia R. 《Journal of Optimization Theory and Applications》2021,190(1):259-273
Journal of Optimization Theory and Applications - This paper proposes and analyzes a globalized version of the Newton method for finding a singularity of the nonsmooth vector fields. Basically, the... 相似文献
3.
Maeva Chaupard Marta de Frutos Ruxandra Gref 《Particle & Particle Systems Characterization》2021,38(9):2100022
Drug nanocarriers (NCs) with sizes usually below 200 nm are gaining increasing interest in the treatment of severe diseases such as cancer and infections. Characterization methods to investigate the morphology and physicochemical properties of multifunctional NCs are key in their optimization and in the study of their in vitro and in vivo fate. Whereas a variety of methods has been developed to characterize “bulk” NCs in suspension, the scope of this review is to describe the different approaches for the NC characterization on an individual basis, for which fewer techniques are available. The accent is put on methods devoid of labelling, which could lead to artefacts. For each characterization method, the principles and approaches to analyze the data are presented in an accessible manner. Aspects related to sample preparation to avoid artefacts are indicated, and emphasis is put on examples of applications. NC characterization on an individual basis allows gaining invaluable information in terms of quality control, on: i) NC localization and fate in biological samples; ii) NC morphology and crystallinity; iii) distribution of the NC components (drugs, shells), and iv) quantification of NCs’ chemical composition. The individual characterization approaches are expected to gain increasing interest in the near future. 相似文献
4.
Fernandes Joo Lucas Ribeiro e de Souza Altair Lcio de Faria Geraldo Lcio 《Journal of Thermal Analysis and Calorimetry》2022,147(12):6593-6603
Journal of Thermal Analysis and Calorimetry - The hot coil slump is a recurrent problem in the manufacturing process of medium and high equivalent carbon steel plates. Even with the success of the... 相似文献
5.
Martin Obst 《Aequationes Mathematicae》2018,92(1):135-163
Measuring angles in the Euclidean plane is a well-known topic, but for general normed planes there exists a variety of different concepts. These can be of a special kind, e.g. also preserving special orthogonality types. But these concepts are no angle measures in the sense of measure theory since they are not additive. This motivates us to define a new angle measure for normed planes that is in fact a measure in the sense of measure theory. Furthermore, we look at related types of rotation and reflection. 相似文献
6.
We analyze isolated resonance curves (IRCs) in single-degree-of-freedom systems possessing nonlinear damping. Through the combination of singularity theory and the averaging method, the onset and merging of IRCs, which coincide to isola and simple bifurcation singularities, respectively, can be analytically predicted. Numerical simulations confirm the accuracy of the analytical developments. Another important finding of this paper is that we unveil a geometrical connection between the topology of the damping force and IRCs. Specifically, we demonstrate that extremas and zeros of the damping force correspond to the appearance and merging of IRCs. Considering a damping force possessing several minima and maxima confirms the general validity of the analytical result. It also evidences a very complex scenario for which different IRCs are created, co-exist and then merge together to form a super IRC which eventually merges with the main resonance peak. 相似文献
7.
Arkadiusz Lewandowski 《Archiv der Mathematik》2018,111(5):503-511
We give the parameter version of a localization theorem for the Bergman metric near the boundary points of strictly pseudoconvex domains. The approximation theorem for square integrable holomorphic functions on such domains in the spirit of Graham-Kerzman is proved in the hereby paper, as well. 相似文献
8.
9.
The paper presents an interphase cohesive zone model (CZM) incorporating stress multi-axiality devised to capture, by simplified micro-modeling, the influence of the in-plane strain and stress state in the mechanical response of the CZM. Moreover, the model is able to account for the Poisson-related effect in the interphase, which can play an important role in the modeling of heterogeneous masonry elements. From the constitutive point of view, the proposed formulation couples damage and friction by addressing a smooth transition from a quasi-brittle response to a residual frictional behavior described by a Coulomb law with unilateral contact. As in-plane stresses are accounted for, damage activation and evolution are governed by a Drucker–Prager law with linear softening. A predictor-corrector procedure based on a backward Euler scheme is detailed for integrating the nonlinear evolutive problem together with the related tangent operator which consistently linearizes the algorithmic strategy. This framework is embedded into a kinematically-enriched finite element interphase formulation incorporating stress multi-axiality. The modeling features of the resulting numerical tool are tested both at the local level, for the typical interphase point, and in meso-structural tests consisting of brick-mortar triplets, investigating the capability of the proposed model and numerical procedure to simulate the brick-mortar decohesion mechanism during confined slip tests. 相似文献
10.
We describe the static charge susceptibility and correlation function of the charge density in the twodimensional t-J-V model based on the method of equations of motion for the relaxation functions of the Hubbard operators. We obtain the dependence of the susceptibility and correlation function on the hole concentration and temperature. Charge density waves can develop if the intersite Coulomb interaction is sufficiently strong. 相似文献