全文获取类型
收费全文 | 813篇 |
免费 | 67篇 |
专业分类
化学 | 592篇 |
晶体学 | 4篇 |
力学 | 24篇 |
数学 | 79篇 |
物理学 | 181篇 |
出版年
2023年 | 6篇 |
2022年 | 16篇 |
2021年 | 20篇 |
2020年 | 24篇 |
2019年 | 26篇 |
2018年 | 16篇 |
2017年 | 13篇 |
2016年 | 44篇 |
2015年 | 26篇 |
2014年 | 24篇 |
2013年 | 34篇 |
2012年 | 54篇 |
2011年 | 73篇 |
2010年 | 35篇 |
2009年 | 26篇 |
2008年 | 40篇 |
2007年 | 41篇 |
2006年 | 35篇 |
2005年 | 35篇 |
2004年 | 34篇 |
2003年 | 24篇 |
2002年 | 17篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 18篇 |
1996年 | 10篇 |
1995年 | 9篇 |
1994年 | 17篇 |
1993年 | 9篇 |
1992年 | 6篇 |
1991年 | 14篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1983年 | 6篇 |
1981年 | 3篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 8篇 |
1973年 | 5篇 |
1968年 | 5篇 |
1967年 | 5篇 |
1966年 | 3篇 |
1960年 | 4篇 |
1958年 | 4篇 |
1938年 | 3篇 |
排序方式: 共有880条查询结果,搜索用时 250 毫秒
131.
John Bamberg S.P. Glasby Luke Morgan Alice C. Niemeyer 《Journal of Pure and Applied Algebra》2019,223(12):5428-5429
We give a correction to Fig. 1 and supporting text published in the paper: ‘Maximal linear groups induced on the Frattini quotient of a p-group’, J. Pure Appl. Algebra 222 (10) (2018) 2931–2951. 相似文献
132.
Hoeben W. F. L. M. van Ooij P. P. Schram D. C. Huiskamp T. Pemen A. J. M. Lukeš P. 《Plasma Chemistry and Plasma Processing》2019,39(3):597-626
Plasma Chemistry and Plasma Processing - Plasma activated deionized water from a hot arc 150 W PAW synthesizer has been analyzed for nitrite, nitrate and peroxide densities. Observed nitrite and... 相似文献
133.
134.
135.
Atika Muhammad Dr. Graziano Di Carmine Luke Forster Dr. Carmine D'Agostino 《Chemphyschem》2020,21(11):1101-1106
Solvent effects in homogeneous catalysis are known to affect catalytic activity. Whilst these effects are often described using qualitative features, such as Kamlet-Taft parameters, experimental tools able to quantify and reveal in more depth such effects have remained unexplored. In this work, PFG NMR diffusion and T1 relaxation measurements have been carried out to probe solvent effects in the homogeneous catalytic reduction of propionaldehyde to 1-propanol in the presence of aluminium isopropoxide catalyst. Using data on diffusion coefficients it was possible to estimate trends in aggregation of different solvents. The results show that solvents with a high hydrogen-bond accepting ability, such as ethers, tend to form larger aggregates, which slow down the molecular dynamics of aldehyde molecules, as also suggested by T1 measurements, and preventing their access to the catalytic sites, which results in the observed decrease of catalytic activity. Conversely, weakly interacting solvents, such as alkanes, do not lead to the formation of such aggregates, hence allowing easy access of the aldehyde molecules to the catalytic sites, resulting in higher catalytic activity. The work reported here is a clear example on how combining traditional catalyst screening in homogeneous catalysis with NMR diffusion and relaxation time measurements can lead to new physico-chemical insights into such systems by providing data able to quantify aggregation phenomena and molecular dynamics. 相似文献
136.
Cover Picture: Mild and Low‐Pressure fac‐Ir(ppy)3‐Mediated Radical Aminocarbonylation of Unactivated Alkyl Iodides through Visible‐Light Photoredox Catalysis (Chem. Eur. J. 27/2016)
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
137.
Gene delivery by electroporation after dielectrophoretic positioning of cells in a non-uniform electric field 总被引:1,自引:0,他引:1
MacQueen LA Buschmann MD Wertheimer MR 《Bioelectrochemistry (Amsterdam, Netherlands)》2008,72(2):141-148
We report the use of dielectrophoresis (DEP) to position U-937 monocytes within a non-uniform electric field, prior to electroporation (EP) for gene delivery. DEP positioning and EP pulsing were both accomplished using a common set of inert planar electrodes, micro-fabricated on a glass substrate. A single-shell model of the cell's dielectric properties and finite-element modeling of the electric field distribution permitted us to predict the major features of cell positioning. The extent to which electric pulses increased the permeability of the cell membranes to fluorescent molecules and to pEGFPLuc DNA plasmids were found to depend on prior positioning. For a given set of pulse parameters, EP was either irreversible (resulting in cytolysis), reversible (leading to gene delivery), or not detectable, depending on where cells were positioned. Our results clearly demonstrate that position-dependent EP of cells in a non-uniform electric field can be controlled by DEP. 相似文献
138.
139.
Xie F Li D Tyree L Li L Sovkov VB Ivanov VS Magnier S Marjatta Lyyra A 《The Journal of chemical physics》2008,128(20):204313
The Cs(2) 2 (3)Delta(1g) and b (3)Pi(0u) states have been observed by infrared-infrared double resonance spectroscopy for the first time. 221 2 (3)Delta(1g)<--A (1)Sigma(u) (+)<--X (1)Sigma(g) (+) double resonance lines have been assigned to transitions into the 2 (3)Delta(1g) v=6-13 vibrational levels. Resolved fluorescence into the b (3)Pi(0u) v(')=0-48 levels has been recorded. Molecular constants and potential energy curves are determined by the global fit of the entire set of the experimental data. Theoretical potential energy curves of the 2 (3)Delta(g) and b (3)Pi(u) states have been determined in the framework of the pseudopotential method and are compared with the experimental results. 相似文献
140.
Dhanya Karipal Padinjare Veedu Prof. Luke A. Connal Assoc. Prof. Lara R. Malins 《Angewandte Chemie (International ed. in English)》2023,62(4):e202215470
Electrochemical transformations provide enticing opportunities for programmable, residue-specific peptide modifications. Herein, we harness the potential of amidic side-chains as underutilized handles for late-stage modification through the development of an electroauxiliary-assisted oxidation of glutamine residues within unprotected peptides. Glutamine building blocks bearing electroactive side-chain N,S-acetals are incorporated into peptides using standard Fmoc-SPPS. Anodic oxidation of the electroauxiliary in the presence of diverse alcohol nucleophiles enables the installation of high-value N,O-acetal functionalities. Proof-of-principle for an electrochemical peptide stapling protocol, as well as the functionalization of dynorphin B, an endogenous opioid peptide, demonstrates the applicability of the method to intricate peptide systems. Finally, the site-selective and tunable electrochemical modification of a peptide bearing two discretely oxidizable sites is achieved. 相似文献