全文获取类型
收费全文 | 349篇 |
免费 | 17篇 |
专业分类
化学 | 222篇 |
晶体学 | 1篇 |
数学 | 9篇 |
物理学 | 134篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 25篇 |
2019年 | 14篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 12篇 |
2013年 | 17篇 |
2012年 | 22篇 |
2011年 | 23篇 |
2010年 | 10篇 |
2009年 | 11篇 |
2008年 | 24篇 |
2007年 | 21篇 |
2006年 | 8篇 |
2005年 | 16篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 11篇 |
1999年 | 3篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1994年 | 11篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1990年 | 4篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 7篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 4篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1936年 | 2篇 |
1931年 | 1篇 |
1888年 | 2篇 |
排序方式: 共有366条查询结果,搜索用时 15 毫秒
91.
Kasper Tolborg Prof. Dr. Bo B. Iversen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(66):15010-15029
Rational material design requires a deep understanding about the relationship between the structure and properties of materials, which are both intimately related to their chemical bonding. Through the experimentally observable electron density, chemical bonding can be understood from experimental and theoretical points of view on an equal footing, and advances in accurate X-ray diffraction measurements and computational techniques over the past decades have provided access to electron density distributions in increasingly complex functional materials. In this Review, selected electron density studies from the literature on a wide range of materials classes are presented, including studies of thermoelectric materials, high pressure electrides, coordination polymers and non-linear optical materials. These studies demonstrate how detailed analysis of chemical bonding based on the electron density provides important understanding of materials beyond arguments based on structure and simple chemical concepts. In cases such as understanding the conducting properties of Zintl semiconductors or the effect of mutual electrical polarization in host–guest systems, it is clearly imperative to go beyond structure and examine the chemical bonding in detail. In the Review, the complementarity between theory and experiment is underlined, which allows for mutual validation of new chemical bonding concepts, and indeed experiment and theory may challenge each other based on the different strengths and weaknesses of each method. 相似文献
92.
Marius Flügel Dr. Thomas Waldmann Michael Kasper Dr. Margret Wohlfahrt-Mehrens 《Chemphyschem》2020,21(18):2047-2050
A method based on glow discharge optical emission spectroscopy (GD-OES) depth profiling is developed to detect copper deposition on graphite electrodes for the first time. Commercial 18650 cells with graphite anodes were subject to Cu dissolution by over-discharge to 0 V. On a first approach, the depth profiles for Cu show significant differences for over-discharged cells compared to a baseline graphite electrode from cells discharged to the end-of-discharge voltage. An accumulation of Cu is found on the anode surface by GD-OES, which is consistent with SEM and EDX. The trend of the total Cu amount is compared with ICP-OES measurements. 相似文献
93.
Markus Schwarz Philipp Skrinjar Michael J. Fink Stefan Kronister Thomas Mechtler Panagiotis I. Koukos Alexandre M. J. J. Bonvin David C. Kasper Hannes Mikula 《Chemical science》2020,11(47):12671
We report on the unexpected finding that click modification of iduronyl azides results in a conformational flip of the pyranose ring, which led to the development of a new strategy for the design of superior enzyme substrates for the diagnostic assaying of iduronate-2-sulfatase (I2S), a lysosomal enzyme related to Hunter syndrome. Synthetic substrates are essential in testing newborns for metabolic disorders to enable early initiation of therapy. Our click-flipped iduronyl triazole showed a remarkably better performance with I2S than commonly used O-iduronates. We found that both O- and triazole-linked substrates are accepted by the enzyme, irrespective of their different conformations, but only the O-linked product inhibits the activity of I2S. Thus, in the long reaction times required for clinical assays, the triazole substrate substantially outperforms the O-iduronate. Applying our click-flipped substrate to assay I2S in dried blood spots sampled from affected patients and random newborns significantly increased the confidence in discriminating between these groups, clearly indicating the potential of the click-flip strategy to control the biomolecular function of carbohydrates.Click-triggered flip of the conformation of a sulfated iduronyl azide afforded a superior enzyme substrate to screen for Hunter syndrome. 相似文献
94.
95.
96.
Sebastian Werner Clarissa Glaser Thomas Kasper Trung Nghia Nguyên Lê Prof. Dr. Silvia Gross Prof. Dr. Bernd M. Smarsly 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(3):e202103437
The precise detection of the toxic gas H2S requires reliable sensitivity and specificity of sensors even at minute concentrations of as low as 10 ppm, the value corresponding to typical exposure limits. CuO can be used for H2S dosimetry, based on the formation of conductive CuS and the concomitant significant increase in conductance. In theory, at elevated temperature the reaction is reversed and CuO is formed, ideally enabling repeated and long-term use of one sensor. Yet, the performance of CuO tends to drop upon cycling. Utilizing defined CuO nanorods we thoroughly elucidated the associated detrimental chemical changes directly on the sensors, by Raman and electron microscopy analysis of each step during sensing (CuO→CuS) and regeneration (CuS→CuO) cycles. We find the decrease in the sensing performance is mainly caused by the irreversible formation of CuSO4 during regeneration. The findings allowed us to develop strategies to reduce CuSO4 formation and thus to substantially maintain the sensing stability even for repeated cycles. We achieved CuO-based dosimeters possessing a response time of a few minutes only, even for 10 ppm H2S, and prolonged life-time. 相似文献
97.
Akash Prabhu Robert D. Crapnell Kasper Eersels Bart van Grinsven Aruna K. Kunhiraman Pankaj Singla Jake McClements Craig E. Banks Katarina Novakovic Marloes Peeters 《Current Opinion in Electrochemistry》2022
Biopolymers possess highly favorable properties for electrochemical biosensing such as their inherent biocompatibility, inexpensive nature, and strong interfacial adhesion. In this mini-review, we will focus on chitosan and polydopamine, two of the most commonly used biopolymers, for electrochemical sensing applications. Chitosan is a polysaccharide that exhibits high chemical resistance, offers straightforward modification and cross-linking, and possesses antibacterial properties and mucoadhesion. Polydopamine has the benefit of universal adhesion, in addition to the ability to form self-assembled structures. We will demonstrate how the unique structural and electrochemical features of these biopolymers can be used in a range of electrochemical biosensing platforms. 相似文献
98.
Risgaard R Hansen KB Clausen RP 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(47):13910-13918
Subunit-selective ligands for glutamate receptors remains an area of interest as glutamate is the major excitatory neurotransmitter in the brain and involved in a number of diseased states in the central nervous system (CNS). Few subtype-selective ligands are known, especially among the N-methyl-D-aspartic acid (NMDA) receptor class. Development of these ligands seems to be a difficult task because of the conserved region in the binding site of the NMDA receptor subunits. A few scaffolds have been developed showing potential to differentiate between the NMDA receptors. 相似文献
99.
100.
Krishnamurthy D Kasper GD Namuswe F Kerber WD Narducci Sarjeant AA Moënne-Loccoz P Goldberg DP 《Journal of the American Chemical Society》2006,128(44):14222-14223
The synthesis of a mononuclear, five-coordinate ferrous complex [([15]aneN4)FeII(SPh)](BF4) (1) is reported. This complex is a new model of the reduced active site of the enzyme superoxide reductase (SOR), which is comprised of a [(NHis)4(Scys)FeII] center. Complex 1 reacts with alkylhydroperoxides (tBuOOH, cumenylOOH) at low temperature to give a metastable, dark red intermediate (2a: R = tBu; 2b: R = cumenyl) that has been characterized by UV-vis, EPR, and resonance Raman spectroscopy. The UV-vis spectrum (-80 degrees C) reveals a 526 nm absorbance (epsilon = 2150 M-1 cm-1) for 2a and a 527 nm absorbance (epsilon = 1650 M-1 cm-1) for 2b, indicative of alkylperoxo-to-iron(III) LMCT transitions, and the EPR data (77 K) show that both intermediates are low-spin iron(III) complexes (g = 2.20 and 1.97). Definitive identification of the Fe(III)-OOR species comes from RR spectra, which give nu(Fe-O) = 612 (2a) and 615 (2b) cm-1, and nu(O-O) = 803 (2a) and 795 (2b) cm-1. The assignments for 2a were confirmed by 18O substitution (tBu18O18OH), resulting in a 28 cm-1 downshift for nu(Fe-18O), and a 46 cm-1 downshift for nu(18O-18O). These data show that 2a and 2b are low-spin FeIII-OOR species with weak Fe-O bonds and suggest that a low-spin intermediate may occur in SOR, as opposed to previous proposals invoking high-spin intermediates. 相似文献