全文获取类型
收费全文 | 592篇 |
免费 | 22篇 |
国内免费 | 4篇 |
专业分类
化学 | 410篇 |
晶体学 | 12篇 |
力学 | 7篇 |
数学 | 106篇 |
物理学 | 83篇 |
出版年
2023年 | 7篇 |
2022年 | 11篇 |
2021年 | 10篇 |
2020年 | 12篇 |
2019年 | 9篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 23篇 |
2015年 | 9篇 |
2014年 | 18篇 |
2013年 | 41篇 |
2012年 | 42篇 |
2011年 | 51篇 |
2010年 | 23篇 |
2009年 | 19篇 |
2008年 | 36篇 |
2007年 | 28篇 |
2006年 | 24篇 |
2005年 | 28篇 |
2004年 | 25篇 |
2003年 | 19篇 |
2002年 | 27篇 |
2001年 | 8篇 |
2000年 | 11篇 |
1999年 | 11篇 |
1998年 | 2篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 10篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1985年 | 6篇 |
1984年 | 9篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1966年 | 2篇 |
1938年 | 1篇 |
1922年 | 1篇 |
排序方式: 共有618条查询结果,搜索用时 15 毫秒
61.
Kundu S Bhangale AS Wallace WE Flynn KM Guttman CM Gross RA Beers KL 《Journal of the American Chemical Society》2011,133(15):6006-6011
Enzymes immobilized on solid supports are increasingly used for greener, more sustainable chemical transformation processes. Here, we used microreactors to study enzyme-catalyzed ring-opening polymerization of ε-caprolactone to polycaprolactone. A novel microreactor design enabled us to perform these heterogeneous reactions in continuous mode, in organic media, and at elevated temperatures. Using microreactors, we achieved faster polymerization and higher molecular mass compared to using batch reactors. While this study focused on polymerization reactions, it is evident that similar microreactor based platforms can readily be extended to other enzyme-based systems, for example, high-throughput screening of new enzymes and to precision measurements of new processes where continuous flow mode is preferred. This is the first reported demonstration of a solid supported enzyme-catalyzed polymerization reaction in continuous mode. 相似文献
62.
63.
Kwaku Adu‐Gyamfi Michael J. Boss Kathleen Lynch‐Davis 《School science and mathematics》2019,119(7):396-404
Previous research has investigated the representational translation practices of high school students, high school teachers, and college preservice teachers in various mathematical contexts including linear functions. Findings from qualitative research has frequently led to new notions about participant work and understanding. Many quantitative research has investigated the degree to which some in these populations correctly perform these translations. However, it seems that only infrequently have empirical research investigated findings from qualitative studies and vice versa, and findings regarding one population are rarely compared with findings of another population. This study (a) empirically explores the frequency of success of preservice teachers (N = 80) regarding representational translations in the context of linear functions, (b) quantifies results from previous qualitative, literature‐based research regarding high school students and teachers, and (c) quantitatively compares the results. This study demonstrates that some mathematical representational translations are more difficult than others. 相似文献
64.
Christine N. Morrison Kathleen E. Prosser Ryjul W. Stokes Anna Cordes Nils Metzler-Nolte Seth M. Cohen 《Chemical science》2022,13(32):9450
Correction for ‘Expanding medicinal chemistry into 3D space: metallofragments as 3D scaffolds for fragment-based drug discovery’ by Christine N. Morrison et al., Chem. Sci., 2020, 11, 1216–1225, https://doi.org/10.1039/C9SC05586J.The authors regret that in the original article, inhibitory values reported for some metallofragments were incorrect. Unfortunately, DMSO stock solutions of reportedly active ferrocene-based metallofragments were found to decompose in the presence of light, which resulted in inaccurate inhibition values. The authors maintain that the core conclusions of the paper are accurate and the utility of three-dimensional metal complexes for fragment-based drug discovery has merit.In the original article, ‘class A’ metallofragments are comprised of ferrocene derivatives (Fig. 1). Some of these ferrocene fragments (specifically those containing carbonyl groups) are reported as broadly inhibiting several protein targets. It was noted in our original report that the ferrocene scaffold was likely promiscuous due to its lipophilicity and potential redox activity, but that it might still serve as a useful metallofragment for fragment-based drug discovery (FBDD) campaigns. However, re-evaluation of these compounds against the influenza endonuclease (PAN) failed to reproduce our original inhibition results for the class A metallofragments using freshly prepared stocks, indicating a problem with the materials used in the original study.Open in a separate windowFig. 1Chemical structures of class A metallofragments.Several compounds from class A were originally reported as having near complete (100%) inhibition against PAN endonuclease at an inhibitor concentration of 200 μM (and2).2). However, when re-evaluated under identical conditions, using freshly prepared DMSO stock solutions, inhibition was only observed with one fragment of this class (A22, Fig. 1), with the previously reported highly active fragments (A4, A7–A21, Compound A1 A2 A3 A4 A5 A7 A8 A9 A10 A11 Reported 12 ± 6 <1 <1 45 ± 14 8 ± 7 103 ± 5 103 ± 4 53 ± 5 46 ± 7 90 ± 5 Corrected 3 ± 10 n.d. 18 ± 3 6 ± 3 21 ± 5 9 ± 3 10 ± 5 4 ± 2 16 ± 4 10 ± 7