全文获取类型
收费全文 | 411篇 |
免费 | 16篇 |
国内免费 | 4篇 |
专业分类
化学 | 298篇 |
晶体学 | 3篇 |
力学 | 2篇 |
数学 | 35篇 |
物理学 | 93篇 |
出版年
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 17篇 |
2015年 | 14篇 |
2014年 | 19篇 |
2013年 | 19篇 |
2012年 | 26篇 |
2011年 | 32篇 |
2010年 | 20篇 |
2009年 | 11篇 |
2008年 | 34篇 |
2007年 | 26篇 |
2006年 | 23篇 |
2005年 | 19篇 |
2004年 | 23篇 |
2003年 | 16篇 |
2002年 | 6篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1988年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1975年 | 3篇 |
1973年 | 4篇 |
1972年 | 1篇 |
1971年 | 4篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1959年 | 1篇 |
1939年 | 1篇 |
1931年 | 1篇 |
1903年 | 1篇 |
排序方式: 共有431条查询结果,搜索用时 484 毫秒
31.
Siems T Anagnostopoulos DF Borchert G Gotta D Hauser P Kirch K Simons LM El-Khoury P Indelicato P Augsburger M Chatellard D Egger J 《Physical review letters》2000,84(20):4573-4576
A Doppler broadening of x-ray transitions from pionic nitrogen and muonic oxygen, which is attributed to Coulomb explosion of the molecules, has been observed by using a crystal spectrometer. Large linewidths indicate fast ionization of the molecules and a charge of (3-4)e for the accelerated fragments. 相似文献
32.
U. Hochkirch W. Herrmann R. Stößer K.-P. Moll J. Gallego Llerena M. Linscheid H.-H. Borchert 《Applied magnetic resonance》2008,35(1):173-184
The spectral–spatial electron spin resonance (ESR) imaging experiment provides information about the spatial and spectral
properties of the examined sample, as well as the intensity distribution. Obtaining quantitative statements of the respective
sample requires the usage of reference standards such as diphenylpicrylhydrazyl (DPPH) or charcoal. By means of ultraviolet-visible
spectroscopy a DPPH sample has been quantified to become the reference DPPH standard for the following experiments. Moreover,
charcoal together with DPPH serves as a standard to determine the spatial dimension. An ESR tomographic device has been modified
concerning the sample shaping and arranging in a TE102 resonator to allow the spatially resolved quantitative determination of spin concentrations of spin probes (S = 1/2) with an acceptable error. Only standard ESR equipment has been used except the additional gradient coils and their
computer-aided controls for recording the tomogram. The presented results, i.e., the spatially resolved determination of spin
concentrations, seem to be useful to describe, e.g., transport processes in biological objects. As a first application of
the developed method, the spatial resolution of the effect of ultraviolet irradiation on the concentration of a spin probe
in human skin could be determined. Altogether, the newly introduced method widens the field of applications of ESR spectroscopy
and tomography.
Authors' address: Werner Herrmann, Institute of Pharmacy, Free University Berlin, Kelchstrasse 31, 12169 Berlin, Germany 相似文献
33.
34.
35.
36.
37.
Regan J. Anderson Benjamin J. Compton Ching-wen Tang Astrid Authier-Hall Colin M. Hayman Gene W. Swinerd Renata Kowalczyk Paul Harris Margaret A. Brimble David S. Larsen Olivier Gasser Robert Weinkove Ian F. Hermans Gavin F. Painter 《Chemical science》2015,6(9):5120-5127
It is known that T cells can eliminate tumour cells through recognition of unique or aberrantly expressed antigens presented as peptide epitopes by major histocompatibility complex (MHC) molecules on the tumour cell surface. With recent advances in defining tumour-associated antigens, it should now be possible to devise therapeutic vaccines that expand specific populations of anti-tumour T cells. However there remains a need to develop simpler efficacious synthetic vaccines that possess clinical utility. We present here the synthesis and analysis of vaccines based on conjugation of MHC-binding peptide epitopes to α-galactosylceramide, a glycolipid presented by the nonpolymorphic antigen-presenting molecule CD1d to provoke the stimulatory activity of type I natural killer T (NKT) cells. The chemical design incorporates an enzymatically cleavable linker that effects controlled release of the active components in vivo. Chemical and biological analysis of different linkages with different enzymatic targets enabled selection of a synthetic vaccine construct with potent therapeutic anti-tumour activity in mice, and marked in vitro activity in human blood. 相似文献
38.
Jonathan H. Brown Lisa Orloff Clark Astrid an Huef 《Journal of Pure and Applied Algebra》2017,221(10):2458-2481
The graph groupoids of directed graphs E and F are topologically isomorphic if and only if there is a diagonal-preserving ring ?-isomorphism between the Leavitt path algebras of E and F. 相似文献
39.
From Crofton's formula for Minkowski tensors we derive stereological estimators of translation invariant surface tensors of convex bodies in the n‐dimensional Euclidean space. The estimators are based on one‐dimensional linear sections. In a design based setting we suggest three types of estimators. These are based on isotropic uniform random lines, vertical sections, and non‐isotropic random lines, respectively. Further, we derive estimators of the specific surface tensors associated with a stationary process of convex particles in the model based setting. 相似文献
40.
Godau T Bleifuss SM Müller AL Roth T Hoffmann S Heinemann FW Burzlaff N 《Dalton transactions (Cambridge, England : 2003)》2011,40(24):6547-6554
One-pot syntheses of three new enantiopure heteroscorpionate ligands derived from (+)-camphor or (-)-menthone are described. The ligands are obtained by reacting pyrazoles derived from (+)-camphor or (-)-menthone with sodium hydride and thionyl chloride. Subsequent reactions with pyridine and various aldehydes afford the tripod ligands in multi-gram amounts. Especially the menthopyrazole based ligand 6 showed encouraging ee values up to 69% in the Cu(I) catalysed enantioselective cyclopropanation of styrene with ethyl diazoacetate. 相似文献