全文获取类型
收费全文 | 990篇 |
免费 | 35篇 |
国内免费 | 8篇 |
专业分类
化学 | 700篇 |
晶体学 | 3篇 |
力学 | 21篇 |
数学 | 161篇 |
物理学 | 148篇 |
出版年
2023年 | 8篇 |
2022年 | 33篇 |
2021年 | 42篇 |
2020年 | 29篇 |
2019年 | 28篇 |
2018年 | 13篇 |
2017年 | 15篇 |
2016年 | 44篇 |
2015年 | 20篇 |
2014年 | 47篇 |
2013年 | 71篇 |
2012年 | 61篇 |
2011年 | 87篇 |
2010年 | 50篇 |
2009年 | 38篇 |
2008年 | 51篇 |
2007年 | 56篇 |
2006年 | 47篇 |
2005年 | 43篇 |
2004年 | 41篇 |
2003年 | 23篇 |
2002年 | 28篇 |
2001年 | 15篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1984年 | 3篇 |
1981年 | 3篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1939年 | 2篇 |
1937年 | 5篇 |
1936年 | 4篇 |
1935年 | 2篇 |
1934年 | 9篇 |
1933年 | 6篇 |
1932年 | 4篇 |
1931年 | 4篇 |
1930年 | 2篇 |
1929年 | 5篇 |
1912年 | 3篇 |
1911年 | 2篇 |
1906年 | 3篇 |
1905年 | 2篇 |
排序方式: 共有1033条查询结果,搜索用时 15 毫秒
61.
Du J Zou P Shi M Kwek LC Pan JW Oh CH Ekert A Oi DK Ericsson M 《Physical review letters》2003,91(10):100403
Examples of geometric phases abound in many areas of physics. They offer both fundamental insights into many physical phenomena and lead to interesting practical implementations. One of them, as indicated recently, might be an inherently fault-tolerant quantum computation. This, however, requires one to deal with geometric phases in the presence of noise and interactions between different physical subsystems. Despite the wealth of literature on the subject of geometric phases very little is known about this very important case. Here we report the first experimental study of geometric phases for mixed quantum states. We show how different they are from the well-understood, noiseless, pure-state case. 相似文献
62.
Maria Hoffmann Antoni Konitz Artur Sikorski Urszula Lesińska Maria Bocheńska 《Journal of inclusion phenomena and macrocyclic chemistry》2003,47(3-4):137-142
The synthesis and characterization of the lower rim bis-phosphorylatedtetrakis-p-tert-butyl-25,27-bis(methoxy)calix[4]arenas(compounds 2–4) is presented. The studied compounds were examined as ionophores in ion-selective membrane electrodes, showing selectivity for rubidium, potassium, and for the large and flat guanidinium cations (G+). The correlation wasstudied between the stereochemical structure of the ligands andpotentiometrically determined ion-selectivity. Complex formationconstants in the PVC/BEHS (bis(ethyl)hexyl sebacate) membranes weredetermined. The crystal and molecular structures of compound 4 have been determined by single crystal X-ray diffraction study. 相似文献
63.
GSH and L-His are abundant biomolecules and likely biological ligands for Zn(II) under certain conditions. Potentiometric titrations provide evidence of formation of ternary Zn(II) complexes with GSH and L-His or D-His with slight stereoselectivity in favour of L-His (ca. 1 log unit of stability constant). The solution structure of the ZnH(GSH)(L-His)(H2O) complex at pH 6.8, determined by NMR, includes tridentate L-His, monodentate (sulfur) GSH, and weak interligand interactions. Calculations of competitivity of this complex for Zn(II) binding at pH 7.4 indicate that it is likely to be formed in vivo under conditions of GSH depletion. Otherwise, GSH alone emerges as a likely Zn(II) carrier. 相似文献
64.
Ahmed M. Eissa Michael J.P. Smith Artur Kubilis Jackie A. Mosely Neil R. Cameron 《Journal of polymer science. Part A, Polymer chemistry》2013,51(24):5184-5193
Copper‐catalyzed azide‐alkyne cycloaddition (CuAAC) was used to prepare glycosylated polyethylene (PE)–poly(ethylene glycol) (PEG) amphiphilic block copolymers. The synthetic approach involves preparation of alkyne‐terminated PE‐b‐PEG followed by CuAAC reaction with different azide functionalized sugars. The alkyne‐terminated PE‐b‐PEG was prepared by etherification reaction between hydroxyl‐terminated PE‐b‐PEG (Mn ~ 875 g mol?1) and propargyl bromide and azidoethyl glycosides were prepared by glycosylation of 2‐azidoethanol. Atmospheric pressure solids analysis probe‐mass spectrometry was used as a novel solid state characterization tool to determine the outcome of the CuAAC click reaction and end‐capping of PE‐b‐PEG by the azidoethyl glycoside group. The aqueous solution self‐assembly behavior of these amphiphilic glycosylated polymers was explored by TEM and dye solubilization studies. Carbohydrate‐bearing spherical aggregates with the ability to solubilize a hydrophobic dye were observed. The potential of these amphiphilic glycosylated polymers to self‐assemble via electro‐formation into giant carbohydrate‐bearing polymersomes was also investigated using confocal fluorescence microscopy. An initial bioactivity study of the carbohydrate‐bearing aggregates is furthermore presented. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 5184–5193 相似文献
65.
Juliana Marques Ramos Thiago Martucci Artur Wilson Carbonari Messias de Souza Costa Rajendra Narain Saxena Reiner Vianden 《Hyperfine Interactions》2013,221(1-3):129-136
Electric quadrupole interactions were studied in pure and Mn-doped powder samples and thin films of SnO2 using perturbed γγ angular correlation spectroscopy (PAC). The powder samples were prepared by Sol gel method and the thin film were prepared on the Si (100) substrate by sputtering technique using Sn in the oxygen atmosphere. The samples were characterized by x-ray diffraction, energy dispersive spectroscopy and scanning electron microscopy. The thickness of the film was 100 nm. The average particle size of the SnO2 powder samples was determined to be smaller than 60 nm. The radioactive 111In and 181Hf tracers were introduced in the powder samples during the sol gel chemical process. Radioactive 111In was implanted on the SnO2 thin films using the University of Bonn ion implanter (BONIS). PAC measurements were carried out in a four BaF2 detector spectrometer in the temperature range of 77–973 K for samples annealed at different temperatures. The PAC results for both nuclear probes show the presence of two electric quadrupole interactions. The major fractions in both cases correspond to the substitutional sites in the rutile phase of SnO2. The results are compared with previous PAC measurements. 相似文献
66.
67.
Artur F. Keppler Giselle Cerchiaro João V. Comasseto 《Journal of organometallic chemistry》2008,693(24):3558-3562
The mechanism of the addition reaction of TeCl4 to alkynes was indirectly established by the detection of TeCl3 centered radicals using EPR spin trapping, ESI-MS and ESI-MS/MS characterization. 相似文献
68.
69.
Artur Seher 《Fresenius' Journal of Analytical Chemistry》1986,324(3-4):215-216
70.
Artur Ekert 《International Journal of Theoretical Physics》2008,47(8):2101-2119
This purely recreational paper is about one of the most colorful characters of the Italian Renaissance, Girolamo Cardano,
and the discovery of two basic ingredients of quantum theory, probability and complex numbers. 相似文献