全文获取类型
收费全文 | 1074篇 |
免费 | 55篇 |
国内免费 | 4篇 |
专业分类
化学 | 927篇 |
晶体学 | 5篇 |
力学 | 20篇 |
数学 | 85篇 |
物理学 | 96篇 |
出版年
2023年 | 13篇 |
2022年 | 12篇 |
2021年 | 22篇 |
2020年 | 34篇 |
2019年 | 23篇 |
2018年 | 29篇 |
2017年 | 11篇 |
2016年 | 32篇 |
2015年 | 42篇 |
2014年 | 38篇 |
2013年 | 58篇 |
2012年 | 83篇 |
2011年 | 110篇 |
2010年 | 54篇 |
2009年 | 39篇 |
2008年 | 83篇 |
2007年 | 72篇 |
2006年 | 64篇 |
2005年 | 53篇 |
2004年 | 61篇 |
2003年 | 43篇 |
2002年 | 43篇 |
2001年 | 15篇 |
2000年 | 16篇 |
1999年 | 5篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 6篇 |
1995年 | 14篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 1篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1986年 | 2篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1937年 | 1篇 |
排序方式: 共有1133条查询结果,搜索用时 31 毫秒
101.
Elin S. Karlsson Caroline H. Johnson Sunil Sarda Lisa Iddon Mazhar Iqbal Xiaoli Meng John R. Harding Andrew V. Stachulski Jeremy K. Nicholson Ian D. Wilson John C. Lindon 《Rapid communications in mass spectrometry : RCM》2010,24(20):3043-3051
The use of high‐performance liquid chromatography/mass spectrometry (HPLC/MS) and proton nuclear magnetic resonance (1H NMR) spectroscopy for the kinetic analysis of acyl glucuronide (AG) isomerisation and hydrolysis of the 1‐β‐O‐acyl glucuronides (1‐β‐O‐AG) of phenylacetic acid, (R)‐ and (S)‐α‐methylphenylacetic acid and α,α‐dimethylphenylacetic acid is described and compared. Each AG was incubated in both aqueous buffer, at pH 7.4, and control human plasma at 37°C. Aliquots of these incubations, taken throughout the reaction time‐course, were analysed by HPLC/MS and 1H NMR spectroscopy. In buffer, transacylation reactions predominated, with relatively little hydrolysis to the free aglycone observed. In human plasma incubations the calculated rates of reaction were much faster than for buffer and, in contrast to the observations in buffer, hydrolysis to the free aglycone was a significant contributor to the overall reaction. A diagnostic analytical methodology based on differential mass spectrometric fragmentation of 1‐β‐O‐AGs compared to the 2‐, 3‐ and 4‐positional isomers, which enables selective determination of the former, was confirmed and applied. These findings show that HPLC/MS offers a viable alternative to the more commonly used NMR spectroscopic approach for the determination of the transacylation and hydrolysis reactions of these AGs, with the major advantage of having the capability to do so in a complex biological matrix such as plasma. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
102.
Jean-Philippe Basly Anséline Gradolatto Caroline Teyssier Naric Chantal Canivenc-Lavier 《Monatshefte für Chemie / Chemical Monthly》2003,134(3):355-359
Summary. A selective
column switching high performance liquid chromatographic method has been used for the simultaneous determination of apigenin
and metabolites in rat liver perfusate. This new method clearly separated apigenin and the metabolites with high resolution.
The structures of metabolites were proposed based on selective ion recording and full scan analysis by electrospray ionization
mass spectrometry.
Corresponding author. E-mail: basly@pharma.unilim.fr
Received May 15, 2002; accepted (revised) September 13, 2002 相似文献
103.
This paper extends the results of Goh [1], and Takeuchi and Adachi [2,3] concerning the generalized linear Volterra model. We introduce a piecewise linear Volterra model for a two- species system. The solution of the steady-state problem is then shown to be equivalent to finding the solution to the Generalized Linear Complementarity Problem. We show when this nonnegative equilibrium is unique and globally asymptotically stable in the sense of Goh [1]. 相似文献
104.
105.
Caroline Sart Abdellatif Ouahsine Mohamed Louaked Pierre-Antoine Bois 《Comptes Rendus Mecanique》2002,330(3):159-165
In order to resolve the convection terms in the simulation of coastal flows, we propose a numerical method based on the Total Variation Diminishing scheme completed with the Artificial Compression Method to reduce the artificial diffusion and to sharpen the tracer profile in strong gradient regions. This method was applied successfully at discontinuous regions, but out of these regions a limitation of its application is necessary. An application is made to estimate the width of the fresh water band in the Eastern English Channel. To cite this article: C. Sart et al., C. R. Mecanique 330 (2002) 159–165. 相似文献
106.
107.
108.
109.
Nikolai Kuhnert Daniela Göbel Caroline Thiele Benjamin Renault Bing Tang 《Tetrahedron letters》2006,47(38):6915-6918
The N-alkylation and N-acylation reactions of trianglamine macrocycles are described leading to an efficient synthesis of enantiomerically pure functionalised hexa-amide and hexa-amine trianglamine macrocycles. 相似文献
110.
Formation of a Syndiotactic Organic Polymer Inside a MOF by a [2+2] Photo‐Polymerization Reaction
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. In‐Hyeok Park Dr. Raghavender Medishetty Hyeong‐Hwan Lee Caroline Evania Mulijanto Hong Sheng Quah Prof. Shim Sung Lee Prof. Jagadese J. Vittal 《Angewandte Chemie (International ed. in English)》2015,54(25):7313-7317
Getting suitable crystals for single‐crystal X‐ray crystallographic analysis still remains an art. Obtaining single crystals of metal–organic frameworks (MOFs) containing organic polymers poses even greater challenges. Here we demonstrate the formation of a syndiotactic organic polymer ligand inside a MOF by quantitative [2+2] photopolymerization reaction in a single‐crystal‐to‐single‐crystal manner. The spacer ligands with trans,trans,trans‐conformation in the pillared‐layer MOF with guest water molecules in the channels, undergo pedal motion to trans,cis,trans‐conformation prior to [2+2] photo‐cycloaddition reaction and yield single crystals of MOF containing two‐dimensional coordination polymers fused with the organic polymer ligands. We also show that the organic polymer in the single crystals can be depolymerized reversibly by cleaving the cyclobutane rings upon heating. These MOFs also show interesting photoluminescent properties and sensing of small organic molecules. 相似文献