全文获取类型
收费全文 | 21197篇 |
免费 | 3704篇 |
国内免费 | 2742篇 |
专业分类
化学 | 15416篇 |
晶体学 | 332篇 |
力学 | 1202篇 |
综合类 | 198篇 |
数学 | 2164篇 |
物理学 | 8331篇 |
出版年
2024年 | 78篇 |
2023年 | 410篇 |
2022年 | 708篇 |
2021年 | 749篇 |
2020年 | 933篇 |
2019年 | 873篇 |
2018年 | 760篇 |
2017年 | 687篇 |
2016年 | 1091篇 |
2015年 | 1044篇 |
2014年 | 1245篇 |
2013年 | 1634篇 |
2012年 | 2090篇 |
2011年 | 2051篇 |
2010年 | 1398篇 |
2009年 | 1383篇 |
2008年 | 1556篇 |
2007年 | 1384篇 |
2006年 | 1163篇 |
2005年 | 1020篇 |
2004年 | 741篇 |
2003年 | 553篇 |
2002年 | 569篇 |
2001年 | 480篇 |
2000年 | 421篇 |
1999年 | 365篇 |
1998年 | 284篇 |
1997年 | 228篇 |
1996年 | 221篇 |
1995年 | 222篇 |
1994年 | 212篇 |
1993年 | 155篇 |
1992年 | 147篇 |
1991年 | 128篇 |
1990年 | 123篇 |
1989年 | 74篇 |
1988年 | 75篇 |
1987年 | 52篇 |
1986年 | 56篇 |
1985年 | 56篇 |
1984年 | 43篇 |
1983年 | 24篇 |
1982年 | 31篇 |
1981年 | 22篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1977年 | 10篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1974年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
14.
Polypyrrole Shell@3D‐Ni Metal Core Structured Electrodes for High‐Performance Supercapacitors 下载免费PDF全文
Gao‐Feng Chen Yu‐Zhi Su Pan‐Yong Kuang Zhao‐Qing Liu Dao‐Yi Chen Xu Wu Nan Li Prof. Shi‐Zhang Qiao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(12):4614-4621
Three‐dimensional (3D) nanometal films serving as current collectors have attracted much interest recently owing to their promising application in high‐performance supercapacitors. In the process of the electrochemical reaction, the 3D structure can provide a short diffusion path for fast ion transport, and the highly conductive nanometal may serve as a backbone for facile electron transfer. In this work, a novel polypyrrole (PPy) shell@3D‐Ni‐core composite is developed to enhance the electrochemical performance of conventional PPy. With the introduction of a Ni metal core, the as‐prepared material exhibits a high specific capacitance (726 F g?1 at a charge/discharge rate of 1 A g?1), good rate capability (a decay of 33 % in Csp with charge/discharge rates increasing from 1 to 20 A g?1), and high cycle stability (only a small decrease of 4.2 % in Csp after 1000 cycles at a scan rate of 100 mV s?1). Furthermore, an aqueous symmetric supercapacitor device is fabricated by using the as‐prepared composite as electrodes; the device demonstrates a high energy density (≈21.2 Wh kg?1) and superior long‐term cycle ability (only 4.4 % and 18.6 % loss in Csp after 2000 and 5000 cycles, respectively). 相似文献
15.
16.
Luo Dajuan Liu Bingqian Gao Rong Su Lixia Su Yonghuan 《Journal of Solid State Electrochemistry》2022,26(3):749-759
Journal of Solid State Electrochemistry - Cortisol, a steroid hormone, has been confirmed as a kind of biomarker that reflects the stress response of psychobiology and related adverse health... 相似文献
17.
18.
A protocol to correct for intra‐ and interspecific variation in tail hair growth to align isotope signatures of segmentally cut tail hair to a common time line 下载免费PDF全文
19.
Chao Liu Liying Wang Lin Yang Famei Wang Chunhong Xu Jingwei Lv Guanglai Fu Xianli Li Qiang Liu Haiwei Mu Tao Sun Paul K. Chu 《Physics letters. A》2019,383(25):3200-3206
A single-polarization filter comprising a gold-coated photonic crystal fiber based on surface plasmon resonance is designed and investigated. The pattern matching and coupled polarization characteristics analyzed by the full-vector finite element method (FEM) and losses at 1,540 nm are achieved to 1,016.01739 dB/cm (x-pol core mode) and 33.81917 dB/cm (y-pol core mode). The crosstalk (CT) value of the 1,540 nm band is ?853.12653 dB for fiber length and the bandwidth is 850 nm. The working wavelength of the filter ranges from 1,280 nm to 1,540 nm by varying the diameter of outer air holes (), the diameter of inner air holes (), the metal film thickness (t), as well as the liquid refractive index (n). 相似文献
20.
Alessandro Morando Paola Trebeschi Tao Wang 《Journal of Differential Equations》2019,266(9):5397-5430
We show the short-time existence and nonlinear stability of vortex sheets for the nonisentropic compressible Euler equations in two spatial dimensions, based on the weakly linear stability result of Morando and Trebeschi (2008) [20]. The missing normal derivatives are compensated through the equations of the linearized vorticity and entropy when deriving higher-order energy estimates. The proof of the resolution for this nonlinear problem follows from certain a priori tame estimates on the effective linear problem in the usual Sobolev spaces and a suitable Nash–Moser iteration scheme. 相似文献