全文获取类型
收费全文 | 3942篇 |
免费 | 145篇 |
国内免费 | 48篇 |
专业分类
化学 | 2711篇 |
晶体学 | 32篇 |
力学 | 152篇 |
数学 | 355篇 |
物理学 | 885篇 |
出版年
2023年 | 14篇 |
2022年 | 36篇 |
2021年 | 66篇 |
2020年 | 72篇 |
2019年 | 58篇 |
2018年 | 46篇 |
2017年 | 43篇 |
2016年 | 100篇 |
2015年 | 84篇 |
2014年 | 141篇 |
2013年 | 232篇 |
2012年 | 245篇 |
2011年 | 287篇 |
2010年 | 180篇 |
2009年 | 202篇 |
2008年 | 241篇 |
2007年 | 199篇 |
2006年 | 191篇 |
2005年 | 177篇 |
2004年 | 171篇 |
2003年 | 156篇 |
2002年 | 164篇 |
2001年 | 105篇 |
2000年 | 112篇 |
1999年 | 60篇 |
1998年 | 56篇 |
1997年 | 48篇 |
1996年 | 62篇 |
1995年 | 50篇 |
1994年 | 45篇 |
1993年 | 44篇 |
1992年 | 29篇 |
1991年 | 28篇 |
1990年 | 25篇 |
1989年 | 33篇 |
1988年 | 17篇 |
1987年 | 26篇 |
1986年 | 26篇 |
1985年 | 33篇 |
1984年 | 28篇 |
1983年 | 29篇 |
1982年 | 19篇 |
1981年 | 21篇 |
1980年 | 12篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 16篇 |
1976年 | 20篇 |
1975年 | 17篇 |
1974年 | 10篇 |
排序方式: 共有4135条查询结果,搜索用时 0 毫秒
101.
M. Bonesini E. Bonvin R. Bopp L. J. Carroll A. J. Cass D. Cavalli G. Costa S. U. Chung M. Donnat P. A. Dorsaz M. Feliks J. R. Fischer L. Fluri F. Gianotti S. Jack J. N. Jackson M. N. Kienzle-Focacci J. G. Lynch L. Mandelli M. Martin L. Mathys A. Maxwell M. Mazzanti P. J. Negus S. Pensotti-Rancoita L. Perini D. Perrin R. W. Poultney W. H. Range L. Rosselet S. W. Snow A. S. Thompson R. M. Turnbull J. Wells M. Werlen WA Collaboration 《Zeitschrift fur Physik C Particles and Fields》1989,44(1):71-78
The structure of events associated with the production of direct photons in π? p, π+ p andpp reactions of 280 GeV/c has been studied using data from the WA 70 experiment at the CERN SPS. Results are presented on the distributions of the fractional momenta of the colliding partons and on the fragmentation of the recoil jet and a comparison is made with predictions using the structure functions of Duke and Owens in the Lund Monte Carlo with string fragmentation. 相似文献
102.
103.
Chun SH Chai YS Jeon BG Kim HJ Oh YS Kim I Kim H Jeon BJ Haam SY Park JY Lee SH Chung JH Park JH Kim KH 《Physical review letters》2012,108(17):177201
We find the realization of large converse magnetoelectric (ME) effects at room temperature in a magnetoelectric hexaferrite Ba0.52Sr2.48Co2Fe24O41 single crystal, in which rapid change of electric polarization in low magnetic fields (about 5 mT) is coined to a large ME susceptibility of 3200 ps/m. The modulation of magnetization then reaches up to 0.62μ(B)/f.u. in an electric field of 1.14 MV/m. We find further that four ME states induced by different ME poling exhibit unique, nonvolatile magnetization versus electric field curves, which can be approximately described by an effective free energy with a distinct set of ME coefficients. 相似文献
104.
James A. Levitt Marina K. Kuimova Gokhan Yahioglu Pei-Hua Chung Klaus Suhling David Phillips 《中国光学快报(英文版)》2010,(10):926-930
Fluorescence liftime imaging (FLIM) of modified hydrophobic bodipy dyes that act as fluorescent molecular rotors shows that the fluorescence lifetime of these probes is a function of the microviscosity of their environment. Incubating cells with these dyes, we find a punctate and continuous distribution of the dye in cells. The viscosity value obtained in what appears to be endocytotic vesicles in living cells is around 100 times higher than that of water and of cellular cytoplasm.Time-resolved fluorescence anisotropy measurements also yield rotational correlation times consistent with large microviscosity values. In this way, we successfully develop a practical and versatile approach to map the microviscosity in cells based on imaging fluorescent molecular rotors. 相似文献
105.
Xia Yang Jun Xu Liujiang Xi Yanli Yao Qingdan Yang C. Y. Chung Chun-Sing Lee 《Journal of nanoparticle research》2012,14(6):1-6
One-dimensional ordered quantum-ring chains are fabricated on a quantum-dot superlattice template by molecular beam epitaxy. The quantum-dot superlattice template is prepared by stacking multiple quantum-dot layers and quantum-ring chains are formed by partially capping quantum dots. Partially capping InAs quantum dots with a thin layer of GaAs introduces a morphological change from quantum dots to quantum rings. The lateral ordering is introduced by engineering the strain field of a multi-layer InGaAs quantum-dot superlattice. 相似文献
106.
K.C. Chung C.S. Wang A.J. Santiago J.W. Zhang 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):27-39
Nuclear matter equations of state based on Skyrme, Myers-Swiatecki and Tondeur interactions are written as polynomials of
the cubic root of density, with coefficients that are functions of the relative neutron excess δ. In the extrapolation toward
states far away from the standard one, it is shown that the asymmetry dependence of the critical point ( ,) depends on the model used. However, when the equations of state are fitted to the same standard state, the value of is almost the same in Skyrme and in Myers-Swiatecki interactions, while is much lower in Tondeur interaction. Furthermore,
does not depend sensitively on the choice of the parameter γ in Skyrme interaction.
Received: 5 May 2000 / Accepted: 16 January 2001 相似文献
107.
Hsu Yu-Hsuan Hsieh Hui-Ling Viswanathan Geetha Voon Siew Hui Kue Chin Siang Saw Wen Shang Yeong Chai Hong Azlan Che Ahmad Imae Toyoko Kiew Lik Voon Lee Hong Boon Chung Lip Yong 《Journal of nanoparticle research》2017,19(11):1-15
Journal of Nanoparticle Research - Over the last years, an environmentally friendly and economically efficient way of nanoparticle production has been found in the biosynthesis of metal... 相似文献
108.
109.
In this paper,we consider a possible modification of the de Sitter and anti-de Sitter space for the extended uncertainty principle.For the modified anti-de Sitter model we discuss the representation and wave functions of the momentum operator for a one-dimensional box problem.Also,we consider modified Snyder and anti-Snyder models for the generalized uncertainty principle.Then,we assume the Hamiltonian with different potential and solve the Heisenberg algebra for the modified(anti)-de Sitter and(anti)-Snyder models in both position and in the momentum space. 相似文献
110.
A scheme using ion-exchange methods is described for the analysis of monazites and monazite concentrates. The sample is opened up with concentrated sulphuric acid, and the resultant solution is applied to a column of Zeocarb 225 resin. After phosphate has been washed out, lead, aluminium, titanium, iron, uranium, calcium and magnesium are eluted with N hydrochloric acid and determined by specific, mainly spectrophotometric, methods. Rare earth elements are eluted with 3 N hydrochloric acid. Cerium is separated from the other rare earths by solvent extraction of its nitrate with methyl iso-butyl ketone; both groups are determined gravimetrically. Thorium is eluted from the ion-exchange resin with 3.6 N sulphuric acid and determined spectrophotometrically with thorin.The sulphuric acid-insoluble minerals are brought into solution by a double fusion method, and the determinations are carried out by a combination of ion-exchange and photometric procedures. Silica, phosphorus pentoxide, tin and chromium are determined by photometric methods, using separate portions of the sample.Lanthanum, yttrium and ytterbium are determined in a 1 M perchloric acid solution of the mixed rare earth oxides (less cerium) using flame photometry. Samarium, praseodymium and neodymium are determined by spectrophotometry. 相似文献