全文获取类型
收费全文 | 402篇 |
免费 | 32篇 |
国内免费 | 1篇 |
专业分类
化学 | 315篇 |
晶体学 | 1篇 |
力学 | 4篇 |
数学 | 49篇 |
物理学 | 66篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 1篇 |
2021年 | 10篇 |
2020年 | 7篇 |
2019年 | 15篇 |
2018年 | 13篇 |
2017年 | 7篇 |
2016年 | 23篇 |
2015年 | 17篇 |
2014年 | 12篇 |
2013年 | 25篇 |
2012年 | 22篇 |
2011年 | 38篇 |
2010年 | 16篇 |
2009年 | 12篇 |
2008年 | 28篇 |
2007年 | 27篇 |
2006年 | 23篇 |
2005年 | 31篇 |
2004年 | 22篇 |
2003年 | 23篇 |
2002年 | 13篇 |
2001年 | 7篇 |
2000年 | 3篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有435条查询结果,搜索用时 36 毫秒
1.
Algebras and Representation Theory - We would like to correct two errors in our paper Involutions of type G2 over a field of characteristic 2 [2]. 相似文献
2.
Nitrite reduction by a copper complex featuring a proton-responsive tripodal ligand is demonstrated. Gaseous nitric oxide was confirmed as the sole NOX by-product in quantitative yield. DFT calculations predict that nitrite reduction occurs via a proton and electron transfer process mediated by the ligand. The reported mechanism parallels nitrite reduction by copper nitrite reductase. 相似文献
3.
4.
Dr. Andrew Ballard Dr. Stefania Narduolo Dr. Hiwa O. Ahmed Nathaniel I. Keymer Dr. Nabil Asaad Dr. David A. Cosgrove Dr. Niklaas J. Buurma Dr. Andrew G. Leach 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(17):3661-3687
The two enantiomers of a compound often have profoundly different biological properties and thus their liability to racemisation in aqueous solutions is an important piece of information. The authors reviewed the available data concerning the process of racemisation in vivo, in the presence of biological molecules (e.g., racemase enzymes, serum albumin, cofactors and derivatives) and under purely chemical but aqueous conditions (acid, base and other aqueous systems). Mechanistic studies are described critically in light of reported kinetic data. The types of experimental measurement that can be used to effectively determine rate constants of racemisation in various conditions are discussed and the data they provide is summarised. The proposed origins of enzymatic racemisation are presented and suggest ways to promote the process that are different from processes taking place in bulk water. Experimental and computational studies that provide understanding and quantitative predictions of racemisation risk are also presented. 相似文献
5.
Graphene field-effect transistors (GFET) have emerged as powerful detection platforms enabled by the advent of chemical vapor deposition (CVD) production of the unique atomically thin 2D material on a large scale. DNA aptamers, short target-specific oligonucleotides, are excellent sensor moieties for GFETs due to their strong affinity to graphene, relatively short chain-length, selectivity, and a high degree of analyte variability. However, the interaction between DNA and graphene is not fully understood, leading to questions about the structure of surface-bound DNA, including the morphology of DNA nanostructures and the nature of the electronic response seen from analyte binding. This review critically evaluates recent insights into the nature of the DNA graphene interaction and its affect on sensor viability for DNA, small molecules, and proteins with respect to previously established sensing methods. We first discuss the sorption of DNA to graphene to introduce the interactions and forces acting in DNA based GFET devices and how these forces can potentially affect the performance of increasingly popular DNA aptamers and even future DNA nanostructures as sensor substrates. Next, we discuss the novel use of GFETs to detect DNA and the underlying electronic phenomena that are typically used as benchmarks for characterizing the analyte response of these devices. Finally, we address the use of DNA aptamers to increase the selectivity of GFET sensors for small molecules and proteins and compare them with other, state of the art, detection methods. 相似文献
6.
7.
8.
Matthew D. Ryan Jordan C. Theriot Chern-Hooi Lim Haishen Yang Andrew G. Lockwood Nathaniel G. Garrison Sarah R. Lincoln Charles B. Musgrave Garret M. Miyake 《Journal of polymer science. Part A, Polymer chemistry》2017,55(18):3017-3027
The nature of intramolecular charge transfer (CT) of N,N-diaryl dihydrophenazine photocatalysts (PCs) in different solvents is explored in context of their performance in organocatalyzed atom transfer radical polymerization (O-ATRP). PCs having a computationally predicted lowest energy excited state exhibiting CT character can operate a highly controlled O-ATRP in a wide range of solvent polarities, from non-polar hexanes to highly polar N,N-dimethylacetamide. For PCs having a computationally predicted lowest energy excited state not possessing CT character, their ability to operate a controlled O-ATRP is decreased. This study confirms the importance of CT character in the excited state for N,N-diaryl dihydrophenazine PCs, and a deeper understanding of the activity of CT PCs has enabled the synthesis of polymers of low dispersity (<1.10) in a controlled fashion. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3017–3027 相似文献
9.
10.
Nathaniel T. Rebeck Yifan Li Daniel M. Knauss 《Journal of polymer science. Part A, Polymer chemistry》2013,51(24):1770-1778
Poly(phenylene oxide) block and random copolymers are synthesized by oxidative polymerization of 2,6-dimethylphenol and 2,6-diphenylphenol for potential alkaline exchange membrane application. The copolymers are functionalized on the methyl substituted repeat units through a two-step process to produce pendent quaternary ammonium cationic groups. The amount of quaternary ammonium cations and the ion exchange capacity are quantified through titration measurements. Ionic conductivity of the copolymer membranes is measured by electrochemical impedance spectroscopy. Block copolymers show increased bromide conductivity at higher ion exchange capacities compared with the random copolymer analogs. The bromide conductivity for a block copolymer film with an ion exchange capacity of 1.27 mequiv/g reaches 26 mS/cm at 90 °C and 95% relative humidity. The hydroxide conductivity for the same film was measured to be 84 mS/cm at 80 °C and 95% relative humidity. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1770–1778, 2013 相似文献