全文获取类型
收费全文 | 94篇 |
免费 | 7篇 |
专业分类
化学 | 75篇 |
晶体学 | 1篇 |
力学 | 5篇 |
数学 | 5篇 |
物理学 | 15篇 |
出版年
2023年 | 7篇 |
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 4篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 1篇 |
2013年 | 6篇 |
2012年 | 6篇 |
2011年 | 9篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有101条查询结果,搜索用时 15 毫秒
61.
Fan Zhang Andrew J. Allen Lyle E. Levine Gabrielle G. Long Ivan Kuzmenko Jan Ilavsky 《Journal of synchrotron radiation》2018,25(5):1354-1361
This work reports a harmonic‐rejection scheme based on the combination of Si(111) monochromator and Si(220) harmonic‐rejection crystal optics. This approach is of importance to a wide range of X‐ray applications in all three major branches of modern X‐ray science (scattering, spectroscopy, imaging) based at major facilities, and especially relevant to the capabilities offered by the new diffraction‐limited storage rings. It was demonstrated both theoretically and experimentally that, when used with a synchrotron undulator source over a broad range of X‐ray energies of interest, the harmonic‐rejection crystals transmit the incident harmonic X‐rays on the order of 10?6. Considering the flux ratio of fundamental and harmonic X‐rays in the incident beam, this scheme achieves a total flux ratio of harmonic radiation to fundamental radiation on the order of 10?10. The spatial coherence of the undulator beam is preserved in the transmitted fundamental radiation while the harmonic radiation is suppressed, making this scheme suitable not only for current third‐generation synchrotron sources but also for the new diffraction‐limited storage rings where coherence preservation is an even higher priority. Compared with conventional harmonic‐rejection mirrors, where coherence is poorly preserved and harmonic rejection is less effective, this scheme has the added advantage of lower cost and footprint. This approach has been successfully utilized at the ultra‐small‐angle X‐ray scattering instrument at the Advanced Photon Source for scattering, imaging and coherent X‐ray photon correlation spectroscopy experiments. With minor modification, the harmonic rejection can be improved by a further five orders of magnitude, enabling even more performance capabilities. 相似文献
62.
63.
Anshul Sharma Abdollah Neshat Cory J. Mahnen Alek d. Nielsen Jacob Snyder Tory L. Stankovich Benjamin G. Daum Emily M. LaSpina Gabrielle Beltrano Yunxiang Gao Shuo Li Byung‐Woo Park Robert J. Clements Ernest J. Freeman Christopher Malcuit Jennifer A. McDonough LaShanda T. J. Korley Torsten Hegmann Elda Hegmann 《Macromolecular bioscience》2015,15(2):292-292
64.
Biocompatible,Biodegradable and Porous Liquid Crystal Elastomer Scaffolds for Spatial Cell Cultures 下载免费PDF全文
Anshul Sharma Abdollah Neshat Cory J. Mahnen Alek d. Nielsen Jacob Snyder Tory L. Stankovich Benjamin G. Daum Emily M. LaSpina Gabrielle Beltrano Yunxiang Gao Shuo Li Byung‐Wook Park Robert J. Clements Ernest J. Freeman Christopher Malcuit Jennifer A. McDonough LaShanda T. J. Korley Torsten Hegmann Elda Hegmann 《Macromolecular bioscience》2015,15(2):200-214
65.
Windmiller JR Bandodkar AJ Valdés-Ramírez G Parkhomovsky S Martinez AG Wang J 《Chemical communications (Cambridge, England)》2012,48(54):6794-6796
The realization of epidermal chemical sensing requires a fabrication methodology compatible with the non-planarity and irregularities of the human anatomy. This communication describes the development of printed temporary transfer tattoo (T3) electrochemical sensors for physiological and security monitoring of chemical constituents leading to the demonstration of 'electronic skin'. 相似文献
66.
This paper describes a number of articles that have been published on amino acid analysis using CE during the period from June 2003 to May 2005. This review article follows the previous ones of Smith (Electrophoresis 1999, 20, 3078-3083), Prata et al. (Electrophoresis 2001, 22, 4129-4138), and Poinsot et al. (Electrophoresis 2003, 24, 4047-4062). Several new developments in amino acid analysis with CE are reported concerning UV detection, LIF, MS, and NMR. In addition, we describe articles concerning clinical and pharmaceutical studies, neuroclinical applications, and agricultural and food analysis. 相似文献
67.
Gabrielle Viennet 《Probability Theory and Related Fields》1997,107(4):467-492
This paper investigates the problem of density estimation for absolutely regular observations. In a first part, we state
two important results: a new variance inequality and a Rosenthal type inequality. This allows us to study the ?
p
-integrated risk, p≧ 2, of a large class of density estimators including kernel or projection estimators. Under the summability condition on the
mixing coefficients ∑
k≧ 0
(k+1)
p− 2
β
k
<∞, the rates obtained are those known to be optimal in the independent setting.
Received: 17 October 1995 / In revised form: 26 October 1996 相似文献
68.
Gordon KC David G Walsh TJ 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,72(1):209-213
The spectral properties of 1,6,7,12,13,18-hexaazatrinaphthylene (HATN) and a number of related compounds are modeled using density functional theory, B3LYP. The calculations predict the frequencies with mean absolute deviation of 6 cm(-1) and there is little improvement on going to basis sets larger than 6-31 G(d). The substituent effects on the observed spectra are modeled effectively in both frequency shifts and relative intensities. The electronic properties may be predicted using TD-DFT and these are in very good agreement, in terms of transition energies and intensities, with the experimental data. 相似文献
69.
Daniel P. Downes James H. P. Collins Bimala Lama Huadong Zeng Tan Nguyen Gabrielle Keller Marcelo Febo Joanna R. Long 《Chemphyschem》2019,20(2):216-230
The noninvasive, quantitative ability of nuclear magnetic resonance (NMR) spectroscopy to characterize small molecule metabolites has long been recognized as a major strength of its application in biology. Numerous techniques exist for characterizing metabolism in living, excised, or extracted tissue, with a particular focus on 1H-based methods due to the high sensitivity and natural abundance of protons. With the increasing use of high magnetic fields, the utility of in vivo 1H magnetic resonance spectroscopy (MRS) has markedly improved for measuring specific metabolite concentrations in biological tissues. Higher fields, coupled with recent developments in hyperpolarization, also enable techniques for complimenting 1H measurements with spectroscopy of other nuclei, such as 31P and 13C, and for combining measurements of metabolite pools with metabolic flux measurements. We compare ex vivo and in vivo methods for studying metabolism in the brain using NMR and highlight insights gained through using higher magnetic fields, the advent of dissolution dynamic nuclear polarization, and combining in vivo MRS and ex vivo NMR approaches. 相似文献
70.
Guotao Sun Yao Xie Yuxin Wang Gabrielle A. Mandl Steven L. Maurizio Prof. Hongjie Zhang Prof. Xavier Ottenwaelder Prof. John A. Capobianco Prof. Lining Sun 《Angewandte Chemie (International ed. in English)》2023,62(24):e202304591
Lanthanide upconversion luminescence in nanoparticles has prompted continuous breakthroughs in information storage, temperature sensing, and biomedical applications, among others. Achieving upconversion luminescence at the molecular scale is still a critical challenge in modern chemistry. In this work, we explored the upconversion luminescence of solution dispersions of co-crystals composed of discrete mononuclear Yb(DBM)3Bpy and Eu(DBM)3Bpy complexes (DBM: dibenzoylmethane, Bpy: 2,2′-bipyridine). The 613 nm emission of Eu3+ was observed under excitation of Yb3+ at 980 nm. From the series of molecular assemblies studied, the most intense luminescence was obtained for a 1 : 1 molar ratio of Yb3+ : Eu3+, resulting in a high quantum yield of 0.67 % at 2.1 W cm−2. The structure and energy transfer mechanism of the assemblies were fully characterized. This is the first example of an Eu3+-based upconverting system composed of two discrete mononuclear lanthanide complexes present as co-crystals in non-deuterated solution. 相似文献