全文获取类型
收费全文 | 10487篇 |
免费 | 224篇 |
国内免费 | 106篇 |
专业分类
化学 | 6108篇 |
晶体学 | 90篇 |
力学 | 366篇 |
综合类 | 6篇 |
数学 | 1703篇 |
物理学 | 2544篇 |
出版年
2022年 | 100篇 |
2021年 | 132篇 |
2020年 | 132篇 |
2019年 | 134篇 |
2018年 | 126篇 |
2017年 | 109篇 |
2016年 | 193篇 |
2015年 | 179篇 |
2014年 | 182篇 |
2013年 | 608篇 |
2012年 | 370篇 |
2011年 | 458篇 |
2010年 | 338篇 |
2009年 | 294篇 |
2008年 | 428篇 |
2007年 | 384篇 |
2006年 | 362篇 |
2005年 | 326篇 |
2004年 | 353篇 |
2003年 | 287篇 |
2002年 | 319篇 |
2001年 | 224篇 |
2000年 | 199篇 |
1999年 | 159篇 |
1998年 | 123篇 |
1997年 | 135篇 |
1996年 | 161篇 |
1995年 | 129篇 |
1994年 | 125篇 |
1993年 | 156篇 |
1992年 | 159篇 |
1991年 | 161篇 |
1990年 | 119篇 |
1989年 | 120篇 |
1988年 | 134篇 |
1987年 | 182篇 |
1986年 | 148篇 |
1985年 | 199篇 |
1984年 | 186篇 |
1983年 | 144篇 |
1982年 | 171篇 |
1981年 | 176篇 |
1980年 | 174篇 |
1979年 | 170篇 |
1978年 | 170篇 |
1977年 | 164篇 |
1976年 | 141篇 |
1975年 | 159篇 |
1974年 | 132篇 |
1973年 | 129篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
JETP Letters - Extraordinary multiparticle effects in quantizing magnetic fields that are manifested in strongly interacting two-dimensional electron systems in MgZnO/ZnO heterostructures have been... 相似文献
2.
3.
4.
5.
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
6.
7.
8.
Hendrik Van Maldeghem 《Journal of Geometry》1997,58(1-2):192-202
We characterize in a geometrical way those Suzuki-Tits ovoids which are defined over a perfect fieidK (or equivalently living inside a self polar symplectic quadrangle). We simplify our axioms in the particular cases that (1) the associated Suzuki group has exactly two orbits in the set of lines ofPG(3,K), and (2) the ovoid is finite.Senior Research Associate at the Belgian National Fund for Scientific Research 相似文献
9.
Photobleaching was studied during recording of confocal scanning laser microscopy. Studies on fluorescent gels of FITC-labeled
dextran were used to evaluate differential bleaching along thez-axis. Differential bleaching along the z-axis was observed and it was seen that this was related to the numerical aperture
of the objective in use. This points to the conclusion that photon energy flux density is an important parameter in photobleaching.
To check if photon energy flux density heterogeneity is affected by local variation in the refractive index of the sample,
photobleaching rates were calculated for different fluorescent objects (sections of seeds, animal cells stained with nuclear
stains, immunocytochemistry preparations) and a pronounced similarity was found between photobleaching rates and DIC images. 相似文献
10.
C. Daum L. Hertzberger W. Hoogland R. Jongerius S. Peters P. Van Deurzen V. Chabaud A. Gonzalez-Arroyo B. Hyams H. Tiecke P. Weilhammer A. Dwurazny G. Polok M. Rozanska K. Rybicki M. Turala J. Turnau G. Ascoli H. Backer G. Blanar M. Cerrada H. Dietl J. Gallivan M. Glaubmann R. Klanner E. Lorenz G. Lütjens G. Lutz W. Männer U. Stierlin I. Blakey M. Bowler R. Cashmore J. Loken W. Spalding G. Thompson B. Alper C. Damerell A. Gillman C. Hardwick M. Hotchkiss F. Wickens ACCMOR Collaboration 《Zeitschrift fur Physik C Particles and Fields》1981,10(2):95-100
Muon electron pairs were detected in an Al multiplate spark chamber, exposed to a neutrino beam from the CERN PS. The leptons were not accompanied by other particles, except occasionally by protons. The background came mainly from muon associated π0 production, with one decay gamma lost. It was determined empirically, together with the small contribution from υ e reactions. For electron energies above 2 GeV the background is 5.7±1.5 events, whereas 18 (μe)-candidates have been observed. Hence the effect is established, with a rate of about 10?4 as compared to the muonic reactions above 3 GeV. Charm creation as the origin of this (μe)-production process is excluded; heavy neutral lepton production does not fit the kinematics observed. Instead the events are compatible with the two-body decay of an object with variable invariant mass of order 1 GeV, possibly resulting from axion interactions. 相似文献