全文获取类型
收费全文 | 2418篇 |
免费 | 40篇 |
国内免费 | 12篇 |
专业分类
化学 | 1541篇 |
晶体学 | 16篇 |
力学 | 45篇 |
数学 | 374篇 |
物理学 | 494篇 |
出版年
2022年 | 11篇 |
2021年 | 15篇 |
2020年 | 18篇 |
2019年 | 25篇 |
2017年 | 18篇 |
2016年 | 39篇 |
2015年 | 37篇 |
2014年 | 37篇 |
2013年 | 93篇 |
2012年 | 99篇 |
2011年 | 124篇 |
2010年 | 68篇 |
2009年 | 68篇 |
2008年 | 128篇 |
2007年 | 111篇 |
2006年 | 141篇 |
2005年 | 122篇 |
2004年 | 119篇 |
2003年 | 77篇 |
2002年 | 96篇 |
2001年 | 45篇 |
2000年 | 44篇 |
1999年 | 30篇 |
1998年 | 27篇 |
1997年 | 25篇 |
1996年 | 34篇 |
1995年 | 32篇 |
1994年 | 37篇 |
1993年 | 28篇 |
1992年 | 35篇 |
1991年 | 21篇 |
1990年 | 19篇 |
1989年 | 40篇 |
1988年 | 27篇 |
1987年 | 19篇 |
1986年 | 22篇 |
1985年 | 24篇 |
1984年 | 28篇 |
1983年 | 28篇 |
1982年 | 38篇 |
1981年 | 37篇 |
1980年 | 33篇 |
1979年 | 30篇 |
1978年 | 31篇 |
1977年 | 42篇 |
1976年 | 32篇 |
1975年 | 25篇 |
1974年 | 32篇 |
1973年 | 38篇 |
1972年 | 11篇 |
排序方式: 共有2470条查询结果,搜索用时 15 毫秒
171.
172.
The infrared spectra (700–150 cm?1) of twenty-six complexes of 2-aminomethylpyridine (amp) with first transition series metal(II) ions are discussed. The complexes include the tris(amp) complexes [M(amp)3]2+ the bis(amp) compounds M(amp)2X2 and the mono(amp) complexes M(amp)X2. Assignments of the NH2 rocking modes, v(M-NH2), v(M-py) and ligand modes are based on the effects of isotopic labelling of the amino group and the effects of substitution of the metal ion and halide. The structural implications of the spectra are discussed. 相似文献
173.
Tutte's result for the number of planted plane trees with a given degree partition is rederived by a variety of methods and in particular by a simple piecewise construction technique. A theorem of Gordon and Temple is applied in order to give a general relationship between the number of planted plane trees and the number of rooted plane trees and the degree partition restriction is generalised to type partition. The piecewise construction method is successfully used to derive the number of planted plane trees with a given 2-colour degree partition, also derived by Tutte, and an algorithm for the k-coloured case is developed. This algorithm may be used to obtain more specific results. These models are relevant to the statistical mechanics of polymers and this is discussed briefly. 相似文献
174.
175.
S.F. Biagi M. Bourquin A.J. Britten R.M. Brown H. Burchhart A.A. Carter J.R. Carter Ch. Doré P. Extermann M. Gailloud C.N.P. Gee W.M. Gibson J.C. Gordon R.J. Gray P. Igo-Kemenes W.C. Louis T. Modis P. Mühlemann R. Weill 《Physics letters. [Part B]》1982,112(3):265-270
The α parameter for Ξ? → Λπ? decay has been determined to be αΞ?=?0.462 ± 0.015, from a sample of 1.5 × 105 events recorded in the CERN SPS hyperon beam. This value is 2.5 standard deviations higher than the current world average. 相似文献
176.
177.
Chad?A?Dickey Marcia?N?Gordon Donna?M?Wilcock Donna?L?Herber Melissa?J?Freeman Dave?MorganEmail author 《BMC neuroscience》2005,6(1):7
Background
The pathology of Alzheimer's disease (AD) is comprised of extracellular amyloid plaques, intracellular tau tangles, dystrophic neurites and neurodegeneration. The mechanisms by which these various pathological features arise are under intense investigation. Here, expanding upon pilot gene expression studies, we have further analyzed the relationship between Na+/K+ ATPase and amyloid using APP+PS1 transgenic mice, a model that develops amyloid plaques and memory deficits in the absence of tangle formation and neuronal or synaptic loss. 相似文献178.
Light is shown to exhibit critical and tricritical behavior in passively mode-locked lasers with externally injected pulses. It is a first and unique example of critical phenomena in a one-dimensional many-body light-mode system. The phase diagrams consist of regimes with continuous wave, driven parapulses, spontaneous pulses via mode condensation, and heterogeneous pulses, separated by phase transition lines that terminate with critical or tricritical points. Enhanced non-Gaussian fluctuations and collective dynamics are present at the critical and tricritical points, showing a mode system analog of the critical opalescence phenomenon. The critical exponents are calculated and shown to comply with the mean field theory, which is rigorous in the light system. 相似文献
179.
Heidenreich BJ Elliott OT Charney ND Virgien KA Bridges AW McKeon MA Peck SK Krause D Gordon JE Hunter LR Lamoreaux SK 《Physical review letters》2005,95(25):253004
A new method for the detection of the electron electric dipole moment (EDM) using a solid is described. The method involves the measurement of a voltage induced across the solid by the alignment of the sample's magnetic dipoles in an applied magnetic field, H. A first application of the method to GdIG has resulted in a limit on the electron EDM of 5 x 10(-24)e cm, which is a factor of 40 below the limit obtained from the only previous solid-state EDM experiment. The result is limited by the imperfect discrimination of an unexpectedly large voltage that is even upon the reversal of the sample magnetization. 相似文献
180.