全文获取类型
收费全文 | 4116篇 |
免费 | 178篇 |
国内免费 | 10篇 |
专业分类
化学 | 3078篇 |
晶体学 | 10篇 |
力学 | 112篇 |
数学 | 297篇 |
物理学 | 807篇 |
出版年
2023年 | 25篇 |
2022年 | 30篇 |
2021年 | 60篇 |
2020年 | 109篇 |
2019年 | 68篇 |
2018年 | 43篇 |
2017年 | 33篇 |
2016年 | 106篇 |
2015年 | 117篇 |
2014年 | 138篇 |
2013年 | 176篇 |
2012年 | 227篇 |
2011年 | 269篇 |
2010年 | 145篇 |
2009年 | 152篇 |
2008年 | 200篇 |
2007年 | 222篇 |
2006年 | 201篇 |
2005年 | 172篇 |
2004年 | 144篇 |
2003年 | 110篇 |
2002年 | 112篇 |
2001年 | 101篇 |
2000年 | 99篇 |
1999年 | 56篇 |
1998年 | 43篇 |
1997年 | 37篇 |
1996年 | 58篇 |
1995年 | 36篇 |
1994年 | 57篇 |
1993年 | 29篇 |
1992年 | 47篇 |
1991年 | 37篇 |
1990年 | 35篇 |
1989年 | 34篇 |
1988年 | 29篇 |
1987年 | 37篇 |
1986年 | 27篇 |
1985年 | 38篇 |
1984年 | 28篇 |
1983年 | 34篇 |
1982年 | 38篇 |
1981年 | 27篇 |
1980年 | 22篇 |
1979年 | 26篇 |
1978年 | 24篇 |
1976年 | 23篇 |
1973年 | 25篇 |
1968年 | 22篇 |
1967年 | 28篇 |
排序方式: 共有4304条查询结果,搜索用时 31 毫秒
31.
Induced ferroelectric S*C phases are formed by non-chiral SC host phases doped with chiral dipolar guest molecules. In those mixtures the spontaneous polarization Ps and the tilt angle Θ has been investigated as a function of the mole fraction xG of the chiral dopant. In most cases the reduced polarization P0 = PS/ sin Θ has been found to depend linearly on xG. The polarization power which is defined by δP=(∂P0/∂xG)ΔT is discussed in terms of the molecular structure of the chiral dopants. There are systems in which P0(xG) deviates positively from linearity. This behaviour can be understood by considering a local field correction to P0. By assuming a local field of Lorentz type a theoretical relation for P0(xG) has been derived which explains the experimental results. The effect of a local field is considerable if the transverse dipole moment and the polarizability of the chiral dopant are large. 相似文献
32.
Günter Georg Hoffmann Hans-Jürgen Hochkamp 《Fresenius' Journal of Analytical Chemistry》1992,344(4-5):227-228
Summary The application of a digital signal processor (DSP) to Fourier-transform infrared spectroscopy is described, which allows for near real-time display of the transformed interferograms as spectra. 相似文献
33.
34.
P. Boccaccio L. Vannucci R.A. Ricci G. Vannini R. Dona I. Massa J.P. Coffin P. Fintz G. Guillaume F. Jundt F. Rami P. Wagner 《The European Physical Journal A - Hadrons and Nuclei》1998,1(4):399-406
We studied the sequential binary decay of the systems 32S+45Sc, 76Ge, 89Y, 59Co, 63Cu and 19F+63Cu induced by collisions at ≃6 MeV·A. The two stages of the process have reaction-times compatible with the dynamics of different mechanisms. The study of the
excitation energy partition shows that the reaction mechanism of the first step has influence on the de-excitation of the
primary fragments producing two decay components which have different time scale.
Received: 25 March 1997 / Revised version: 2 December 1997 相似文献
35.
36.
37.
38.
39.
Hubert HuppertzRolf-Dieter Hoffmann Rainer Pöttgen 《Journal of solid state chemistry》2002,169(2):155-159
EuPd0.72In1.28 and EuPt0.56In1.44 were prepared under multianvil high-pressure (10.5 GPa) high-temperature (1500 and 1400 K) conditions from the precursor compounds EuPdIn and EuPtIn. They were investigated by X-ray diffraction on both powders and single crystals: MgZn2-type, space group P63/mmc, a=578.7(1) pm, c=944.9(3) pm, wR2=0.0734, 263 F2 values for EuPd0.72In1.28 and a=591.1(2) pm, c=933.8(2) pm, wR2=0.0853, 151 F2 values for EuPt0.56In1.44 with 13 variable parameters per refinement. Both structures are built up from face- and corner-sharing tetrahedra of palladium (platinum) and indium atoms. The europium cations are located in cavities within the three-dimensional [Pd0.72In1.28] and [Pt0.56In1.44] networks. The 2a and 6 h positions of the tetrahedral networks show mixed Pd/In and Pt/In occupancy in EuPd0.72In1.28 and EuPt0.56In1.44, respectively. The crystal chemistry of these indides is briefly discussed. 相似文献
40.