全文获取类型
收费全文 | 27636篇 |
免费 | 4837篇 |
国内免费 | 3933篇 |
专业分类
化学 | 20646篇 |
晶体学 | 317篇 |
力学 | 1539篇 |
综合类 | 226篇 |
数学 | 3855篇 |
物理学 | 9823篇 |
出版年
2024年 | 19篇 |
2023年 | 479篇 |
2022年 | 560篇 |
2021年 | 779篇 |
2020年 | 1074篇 |
2019年 | 1098篇 |
2018年 | 940篇 |
2017年 | 926篇 |
2016年 | 1355篇 |
2015年 | 1374篇 |
2014年 | 1606篇 |
2013年 | 2137篇 |
2012年 | 2516篇 |
2011年 | 2610篇 |
2010年 | 1871篇 |
2009年 | 1761篇 |
2008年 | 1995篇 |
2007年 | 1742篇 |
2006年 | 1551篇 |
2005年 | 1431篇 |
2004年 | 1188篇 |
2003年 | 949篇 |
2002年 | 1029篇 |
2001年 | 861篇 |
2000年 | 656篇 |
1999年 | 576篇 |
1998年 | 470篇 |
1997年 | 419篇 |
1996年 | 400篇 |
1995年 | 361篇 |
1994年 | 312篇 |
1993年 | 215篇 |
1992年 | 214篇 |
1991年 | 202篇 |
1990年 | 167篇 |
1989年 | 120篇 |
1988年 | 87篇 |
1987年 | 71篇 |
1986年 | 87篇 |
1985年 | 61篇 |
1984年 | 37篇 |
1983年 | 33篇 |
1982年 | 19篇 |
1981年 | 14篇 |
1980年 | 6篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1957年 | 4篇 |
1936年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Meccanica - This paper introduces an analytical approach to optimize the textured bearing with cavitation to improve the load support. For this purpose, a grooved parallel slider bearing is... 相似文献
52.
Nonlinear Dynamics - Two kinds of controllable evolutions of optical solitons are predicted in nonlocal nonlinear media by gradually tuning the characteristic length of response function. On the... 相似文献
53.
In this paper, we prove some well-posedness theorems for the nonlinear massive wave equation (with the mass satisfying the Breitenlohner-Freedman bound) on asymptotically anti-de Sitter spaces. The solution is constructed by contraction mapping method and also as a limit of solutions to an initial boundary value problem with boundary at a finite location in spacetime by finally pushing the boundary out to infinity. The solution obtained is unique within the energy class. 相似文献
54.
International Journal of Theoretical Physics - Entanglement-assisted quantum error-correcting codes (abbreviate to EAQECCs) expand the usual paradigm of quantum error correction by allowing two... 相似文献
55.
Liu Xue Ma Hua Xu Heng Tan Ziqi Liu Qiongzhen Wang Yuedan Shu Hongbo Wang Dong 《Journal of Solid State Electrochemistry》2020,24(1):81-91
Journal of Solid State Electrochemistry - CoS2 nanooctahedrons homogeneously encapsulated by hierarchical porous-reduced graphene oxide and polypyrrole thin film are constructed via a simple... 相似文献
56.
Jiao Jiajia Li Hao Lin Wen Wang Rui Meng Zihan Guo Weibin Zhao Shengqiu Li Junsheng Tang Haolin 《Journal of Solid State Electrochemistry》2020,24(3):771-779
Journal of Solid State Electrochemistry - Practical application of Li-S battery is limited by the fast capacity decay and low coulombic efficiency caused by the shuttling phenomenon. Modification... 相似文献
57.
An exceptional n-cycle in a Hom-finite triangulated category with Serre functor has been recently introduced by Broomhead,Pauksztello and Ploog.When n=1,it is a spherical object.We explicitly determine all the exceptional cycles in the bounded derived category D^b(kQ)of a finite quiver Q without oriented cycles.In particular,if Q is an Euclidean quiver,then the length type of exceptional cycles in D^b(kQ)is exactly the tubular type of Q;if Q is a Dynkin quiver of type E_m(m=6,7,8),or Q is a wild quiver,then there are no exceptional cycles in D^b(kQ);and if Q is a Dynkin quiver of type An or D_n,then the length of an exceptional cycle in D^b(kQ)is either h or h/2,where h is the Coxeter number of Q. 相似文献
58.
Li-Bao Fan Yue-Hui Zhou Fen Zou Huan Guo Jin-Feng Huang Jie-Qiao Liao 《Annalen der Physik》2020,532(8):2000134
The quantum thermalization of the Jaynes–Cummings (JC) model in both equilibrium and non-equilibrium open-system cases is studied, in which the two subsystems, a two-level system and a single-mode bosonic field, are in contact with either two individual heat baths or a common heat bath. It is found that in the individual heat-bath case, the JC model can only be thermalized when either the two heat baths have the same temperature or the coupling of the JC system to one of the two baths is turned off. In the common heat-bath case, the JC system can be thermalized irrespective of the bath temperature and the system–bath coupling strengths. The thermal entanglement in this system is also studied. A counterintuitive phenomenon of vanishing thermal entanglement in the JC system is found and proved. 相似文献
59.
Xiaoke Song Dr. Jun-Peng Wang Dr. Yan Song Prof. Tao Qi Prof. Guo Liang Li 《ChemistryOpen》2020,9(3):272-276
Camouflage and wound healing are two vital functions for cephalopods to survive from dangerous ocean risks. Inspired by these dual functions, herein, we report a new type of healable mechanochromic (HMC) material. The bifunctional HMC material consists of two tightly bonded layers. One layer is composed of polyvinyl alcohol (PVA) and titanium dioxide (TiO2) for shielding. Another layer contains supramolecular hydrogen bonding polymers and fluorochromes for healing. The as-synthesized HMC material exhibits a tunable and reversible mechanochromic function due to the strain-induced surface structure of composite film. The mechanochromic function can be further restored after damage because of the incorporated healable polyurethane. The healing efficiency of the damaged HMC materials can even reach 98 % at 60 °C for 6 h. The bioinspired HMC material is expected to have potential applications in the information encryption and flexible displays. 相似文献
60.
Zheng Tian Prof. Hua Bai Yahui Li Dr. Wei Liu Dr. Junfang Li Prof. Qinghong Kong Prof. Guangcheng Xi 《ChemistryOpen》2020,9(1):80-86
In this paper, the gas-sensing properties of copper oxide porous nanosheets in amorphous and highly crystalline states were comparatively investigated on the premise of almost the same specific surface area, morphology and size. Unexpectedly, the results show that amorphous copper oxide porous nanosheets have much better gas sensing properties than highly crystalline copper oxide to a serious of volatile organic compounds, and the lowest detection limit (LOD) of the amorphous copper oxide porous nanosheets to methanal is even up to 10 ppb. By contrast, the LOD of the highly crystalline copper oxide porous nanosheets to methanal is 95 ppb. Experiments prove that the oxygen vacancies contained in the amorphous copper oxide porous nanosheets play a key role in improving gas sensitivity, which greatly improve the chemical activity of the materials, especially for the adsorption of molecules containing oxygen-groups such as methanal and oxygen. 相似文献