全文获取类型
收费全文 | 399篇 |
免费 | 20篇 |
国内免费 | 1篇 |
专业分类
化学 | 327篇 |
晶体学 | 1篇 |
力学 | 11篇 |
数学 | 33篇 |
物理学 | 48篇 |
出版年
2023年 | 5篇 |
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 7篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 12篇 |
2015年 | 15篇 |
2014年 | 7篇 |
2013年 | 11篇 |
2012年 | 27篇 |
2011年 | 39篇 |
2010年 | 15篇 |
2009年 | 16篇 |
2008年 | 30篇 |
2007年 | 30篇 |
2006年 | 33篇 |
2005年 | 24篇 |
2004年 | 31篇 |
2003年 | 14篇 |
2002年 | 13篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有420条查询结果,搜索用时 31 毫秒
1.
Maëva-Charlotte Kervarec Prof. Dr. Erhard Kemnitz Priv.-Doz. Dr. Gudrun Scholz Dr. Svemir Rudić Prof. Dr. Thomas Braun Prof. Dr. Christian Jäger Dr. Adam A. L. Michalchuk Priv.-Doz. Dr. Franziska Emmerling 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(32):7314-7322
The very strong Lewis acid aluminium chlorofluoride (ACF) was loaded with anhydrous HF. The interaction between the surface of the catalyst and HF was investigated using a variety of characterization methods, which revealed the formation of polyfluorides. Moreover, the reactivity of the HF-loaded ACF towards the hydrofluorination of alkynes was studied. 相似文献
2.
Hiromasa Nishikiori Rudi Agus Setiawan Kyohei Miyashita Katsuya Teshima Tsuneo Fujii 《Photochemistry and photobiology》2014,90(4):747-759
Fluorescein‐dispersing titania gel films were prepared by the acid‐catalyzed sol–gel reaction using a titanium alkoxide solution containing fluorescein. The molecular forms of fluorescein in the films, depending on its acid–base equilibria, and the complex formation and photoinduced electron transfer process between the dye and titania surface were investigated by fluorescence and photoelectric measurements. The titanium species were coordinated to the carboxylate and phenolate‐like groups of the fluorescein species. The quantum efficiencies of the fluorescence quenching and photoelectric conversion were higher upon excitation of the dianion species interacting with the titania, i.e. the dye–titania complex. This result indicated that the dianion form was the most favorable for formation of the dye–titania complex exhibiting the highest electron transfer efficiency. Using nitric acid as the catalyst, the titania surface bonded to the fluorescein instead of the adsorbed nitrate ion during the steam treatment. The dye–titania complex formation played an important role in the electron injection from the dye to the titania conduction band. 相似文献
3.
Dr. Sirine Nouri Dr. Julien Boudet Hiang Dreher-Teo Prof. Frédéric H.-T. Allain Prof. Rudi Glockshuber Dr. Loïc Salmon Dr. Christoph Giese 《Angewandte Chemie (International ed. in English)》2023,62(37):e202305120
In NMR spectroscopy, residual dipolar couplings (RDCs) have emerged as one of the most exquisite probes of biological structure and dynamics. The measurement of RDCs relies on the partial alignment of the molecule of interest, for example by using a liquid crystal as a solvent. Here, we establish bacterial type 1 pili as an alternative liquid-crystalline alignment medium for the measurement of RDCs. To achieve alignment at pilus concentrations that allow for efficient NMR sample preparation, we elongated wild-type pili by recombinant overproduction of the main structural pilus subunit. Building on the extraordinary stability of type 1 pili against spontaneous dissociation and unfolding, we show that the medium is compatible with challenging experimental conditions such as high temperature, the presence of detergents, organic solvents or very acidic pH, setting it apart from most established alignment media. Using human ubiquitin, HIV-1 TAR RNA and camphor as spectroscopic probes, we demonstrate the applicability of the medium for the determination of RDCs of proteins, nucleic acids and small molecules. Our results show that type 1 pili represent a very useful alternative to existing alignment media and may readily assist the characterization of molecular structure and dynamics by NMR. 相似文献
4.
Rebecca Wiesner Holger Zagst Wenkui Lan Stewart Bigelow Peter Holper Göran Hübner Leila Josefsson Claire Lancaster Lili Lo Christopher Lößner Huixin Lu Christian Neusüß Carolin Rüttiger Johannes Schlecht Philipp Schürrle Alexander Selsam Debbie van der Burg Shao-Chun Wang Yunxiao Zhu Hermann Wätzig Cari Sänger-van de Griend 《Electrophoresis》2023,44(15-16):1247-1257
Capillary zone electrophoresis ultraviolet (CZE-UV) has become increasingly popular for the charge heterogeneity determination of mAbs and vaccines. The ε-aminocaproic acid (eACA) CZE-UV method has been used as a rapid platform method. However, in the last years, several issues have been observed, for example, loss in electrophoretic resolution or baseline drifts. Evaluating the role of eACA on the reported issues, various laboratories were requested to provide their routinely used eACA CZE-UV methods, and background electrolyte compositions. Although every laboratory claimed to use the He et al. eACA CZE-UV method, most methods actually deviate from He's. Subsequently, a detailed interlaboratory study was designed wherein two commercially available mAbs (Waters’ Mass Check Standard mAb [pI 7] and NISTmAb [pI 9]) were provided to each laboratory, along with two detailed eACA CZE-UV protocols for a short-end, high-speed, and a long-end, high-resolution method. Ten laboratories participated each using their own instruments, and commodities, showing excellence method performance (relative standard deviations [RSDs] of percent time-corrected main peak areas from 0.2% to 1.9%, and RSDs of migration times from 0.7% to 1.8% [n = 50 per laboratory], analysis times in some cases as short as 2.5 min). This study clarified that eACA is not the main reason for the abovementioned variations. 相似文献
5.
Spectroscopic and Kinetic Evidence for the Crucial Role of Compound 0 in the P450cam‐Catalyzed Hydroxylation of Camphor by Hydrogen Peroxide 下载免费PDF全文
Dr. Alicja Franke Prof. Dr. Rudi van Eldik 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(43):15201-15210
The hydroperoxo iron(III) intermediate P450camFeIII–OOH, being the true Compound 0 (Cpd 0) involved in the natural catalytic cycle of P450cam, could be transiently observed in the peroxo‐shunt oxidation of the substrate‐free enzyme by hydrogen peroxide under mild basic conditions and low temperature. The prolonged lifetime of Cpd 0 enabled us to kinetically examine the formation and reactivity of P450camFeIII–OOH species as a function of varying reaction conditions, such as pH, and concentration of H2O2, camphor, and potassium ions. The mechanism of hydrogen peroxide binding to the substrate‐free form of P450cam differs completely from that observed for other heme proteins possessing the distal histidine as a general acid–base catalyst and is mainly governed by the ability of H2O2 to undergo deprotonation at the hydroxo ligand coordinated to the iron(III) center under conditions of pH≥p${K{{{\rm P450}\hfill \atop {\rm a}\hfill}}}$ . Notably, no spectroscopic evidence for the formation of either Cpd I or Cpd II as products of heterolytic or homolytic O?O bond cleavage, respectively, in Cpd 0 could be observed under the selected reaction conditions. The kinetic data obtained from the reactivity studies involving (1R)‐camphor, provide, for the first time, experimental evidence for the catalytic activity of the P450FeIII–OOH intermediate in the oxidation of the natural substrate of P450cam. 相似文献
6.
7.
M. Sommerfeld A. I. Kartushinskii H. Kohnen Yu. A. Rudi M. T. Khusainov I. N. Shcheglov 《Fluid Dynamics》2000,35(6):872-882
The results of an experimental investigation of the effect of particles on decaying grid-generated turbulence in a downward vertical turbulent gas-particle flow are presented. The dispersed particles were glass spheres with a mean size of 700 m. Titanium dioxide particles with a mean size of 2 m were used as the particle-markers modeling the carrier-medium flow. The turbulence was generated by grids with square cells of two sizes (4.8 and 10 mm) and an impenetrability parameter equal to 0.49 at a mean flow velocity equal to 9.5 m/s. The grid Reynolds numbers were 3000 and 6300. The damping of turbulence by the particles, manifested in an increase in the turbulence decay rate (viscous dissipation) and a decrease in the turbulence energy in the power-consuming spectral band, was detected. 相似文献
8.
9.
10.