全文获取类型
收费全文 | 672篇 |
免费 | 32篇 |
国内免费 | 3篇 |
专业分类
化学 | 484篇 |
晶体学 | 6篇 |
力学 | 14篇 |
数学 | 65篇 |
物理学 | 138篇 |
出版年
2023年 | 3篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 10篇 |
2019年 | 12篇 |
2018年 | 8篇 |
2016年 | 25篇 |
2015年 | 24篇 |
2014年 | 21篇 |
2013年 | 46篇 |
2012年 | 43篇 |
2011年 | 54篇 |
2010年 | 33篇 |
2009年 | 27篇 |
2008年 | 34篇 |
2007年 | 32篇 |
2006年 | 32篇 |
2005年 | 28篇 |
2004年 | 29篇 |
2003年 | 14篇 |
2002年 | 23篇 |
2001年 | 9篇 |
2000年 | 12篇 |
1998年 | 10篇 |
1997年 | 11篇 |
1996年 | 6篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1990年 | 6篇 |
1989年 | 9篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1972年 | 8篇 |
1971年 | 4篇 |
1961年 | 3篇 |
1910年 | 2篇 |
1905年 | 2篇 |
排序方式: 共有707条查询结果,搜索用时 15 毫秒
111.
112.
Humberto Andre Potes-Lesoinne Fernando Ramirez-Alvarez Victor H. Perez-Gonzalez Sergio O. Martinez-Chapa Roberto Carlos Gallo-Villanueva 《Electrophoresis》2022,43(1-2):249-262
The survival of living beings, including humanity, depends on a continuous supply of clean water. However, due to the development of industry, agriculture, and population growth, an increasing number of wastewaters is discarded, and the negative effects of such actions are clear. The first step in solving this situation is the collection and monitoring of pollutants in water bodies to subsequently facilitate their treatment. Nonetheless, traditional sensing techniques are typically laboratory-based, leading to potential diminishment in analysis quality. In this paper, the most recent developments in micro- and nano-electrochemical devices for pollutant detection in wastewater are reviewed. The devices reviewed are based on a variety of electrodes and the sensing of three different categories of pollutants: nutrients and phenolic compounds, heavy metals, and organic matter. From these electrodes, Cu, Co, and Bi showed promise as versatile materials to detect a grand variety of contaminants. Also, the most commonly used material is glassy carbon, present in the detection of all reviewed analytes. 相似文献
113.
Corrigendum: Reactions with a Metalloid Tin Cluster {Sn10[Si(SiMe3)3]4}2−: Ligand Elimination versus Coordination Chemistry
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
114.
Reactions with a Metalloid Tin Cluster {Sn10[Si(SiMe3)3]4}2−: Ligand Elimination versus Coordination Chemistry
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Claudio Schrenk Birgit Gerke Prof. Dr. Rainer Pöttgen Dr. Andre Clayborne Prof. Dr. Andreas Schnepf 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8222-8228
Chemistry that uses metalloid tin clusters as a starting material is of fundamental interest towards understanding the reactivity of such compounds. Since we identified {Sn10[Si(SiMe3)3]4}2? 7 as an ideal candidate for such reactions, we present a further step in the understanding of metalloid tin cluster chemistry. In contrast to germanium chemistry, ligand elimination seems to be a major reaction channel, which leads to the more open metalloid cluster {Sn10[Si(SiMe3)3]3}? 9 , in which the Sn core is only shielded by three Si(SiMe3)3 ligands. Compound 9 is obtained through different routes and is crystallised together with two different countercations. Besides the structural characterisation of this novel metalloid tin cluster, the electronic structure is analysed by 119Sn Mössbauer spectroscopy. Additionally, possible reaction pathways are discussed. The presented first step into the chemistry of metalloid tin clusters thus indicates that, with respect to metalloid germanium clusters, more reaction channels are accessible, thereby leading to a more complex reaction system. 相似文献
115.
We study randomness notions given by higher recursion theory, establishing the relationships Π 1 1 -randomness ? Π 1 1 -Martin-Löf randomness ? Δ 1 1 -randomness = Δ 1 1 -Martin-Löf randomness. We characterize the set of reals that are low for Δ 1 1 randomness as precisely those that are Δ 1 1 -traceable. We prove that there is a perfect set of such reals. 相似文献
116.
Tho Duc Khanh Nguyen Stefania Rabasco Alicia A. Lork Andre Du Toit Prof. Andrew G. Ewing 《Angewandte Chemie (International ed. in English)》2023,62(28):e202304098
We used correlative transmission electron microscopy (TEM) and nanoscale secondary ion mass spectrometry (NanoSIMS) imaging to quantify the contents of subvesicular compartments, and to measure the partial release fraction of 13C-dopamine in cellular nanovesicles as a function of size. Three modes of exocytosis comprise full release, kiss-and-run, and partial release. The latter has been subject to scientific debate, despite a growing amount of supporting literature. We tailored culturing procedures to alter vesicle size and definitively show no size correlation with the fraction of partial release. In NanoSIMS images, vesicle content was indicated by the presence of isotopic dopamine, while vesicles which underwent partial release were identified by the presence of an 127I-labelled drug, to which they were exposed during exocytosis allowing entry into the open vesicle prior to its closing again. Demonstration of similar partial release fractions indicates that this mode of exocytosis is predominant across a wide range of vesicle sizes. 相似文献
117.
Stefan Wellert Henrik Imhof Michael Dolle Hans-Jürgen Altmann André Richardt Thomas Hellweg 《Colloid and polymer science》2008,286(4):417-426
At the present time, considerable efforts are being made to develop new media for the decontamination of a variety of toxic
compounds. In the present contribution, new microemulsions with promising properties are presented. Moreover, the decontamination
of surfaces, with an emphasis on varnished metal surfaces of exterior and interior equipment, is investigated using these
microemulsions. Studies of the phase behavior of the system water–perchloroethylene–IHF–2-propanol are reported and the microemulsion
phases are recognized. The wetting behavior on contaminated surfaces and the extraction capabilities with respect to contaminants
are essential for an efficient decontamination. Hence, suitable microemulsions are identified on the basis of these properties.
The decontamination efficiency of these microemulsions is first estimated on the basis of the ability to wet typical chemical
nonresistant varnished steel sheets, which are authentic model systems for real surfaces. Afterwards, promising microemulsions
and, as reference, different solvents are tested with respect to their capability to solubilize sulfur-mustard agent, again
using realistic surfaces contaminated with this chemical warfare agent. Several microemulsions are found, which have the desired
properties. 相似文献
118.
Skirtach AG Karageorgiev P Bédard MF Sukhorukov GB Möhwald H 《Journal of the American Chemical Society》2008,130(35):11572-11573
Polymeric nanometer-thick membranes or nanomembranes possessing photocontrollable permeability are presented. Microcapsules are used as membrane model systems, while gold nanoparticle aggregates are used as active absorption centers. Upon laser light illumination the membranes change permeability reversibly because nanoparticles transiently affect the nearby polymeric network. Nanomembranes reseal to their impermeable state when the laser is switched off. This presents a novel and simple way of reversible permeability control of interest to intracellular signaling and membranes. 相似文献
119.
Time resolved measurements show that during a desorption electrospray ionization (DESI) experiment, the current initially rises sharply, followed by an exponential decrease to a relatively steady current. When the high voltage on the spray emitter is switched off, the current drops to negative values, suggesting that the direction of current flow in the equivalent DESI circuit is reversed. These data demonstrate that the DESI source behaves as a dc capacitor and that the addition of a surface between the sprayer and the counter electrode in DESI introduces a new electrically active element into the system. The charging and discharging behavior was observed using different surfaces and it could be seen both by making current measurements on a plate at the entrance to the mass spectrometer as well as by measuring ion current in the linear ion trap within the vacuum system of the mass spectrometer. The magnitude of the steady state current obtained without analyte present on the surface is different for different surface materials, and different capacitor time constants of the equivalent RC circuits were calculated for different DESI surfaces. The PTFE surface has by far the greatest time constant and is also able to produce the highest DESI currents. Surface properties play a crucial role in charge transfer during DESI in addition to the effects of the chemical properties of the analyte. It is suggested that surface energy (wettability) is an important factor controlling droplet behavior on the surface. The experimental data are correlated with critical surface tension values of different materials. It is proposed, based on the results presented, that super-hydrophobic materials with extremely high contact angles have the potential to be excellent DESI substrates. It is also demonstrated, using the example of the neurotransmitter dopamine, that the surface charge that develops during a DESI-MS experiment can cause electrochemical oxidation of the analyte. 相似文献
120.
Open‐Pore Two‐Dimensional MFI Zeolite Nanosheets for the Fabrication of Hydrocarbon‐Isomer‐Selective Membranes on Porous Polymer Supports
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)
Han Zhang Prof. Qiang Xiao Prof. Xianghai Guo Prof. Najun Li Prashant Kumar Neel Rangnekar Mi Young Jeon Prof. Shaeel Al‐Thabaiti Prof. Katabathini Narasimharao Prof. Sulaiman Nasir Basahel Prof. Berna Topuz Frank J. Onorato Prof. Christopher W. Macosko Prof. K. Andre Mkhoyan Prof. Michael Tsapatsis 《Angewandte Chemie (International ed. in English)》2016,55(25):7184-7187
Two‐dimensional zeolite nanosheets that do not contain any organic structure‐directing agents were prepared from a multilamellar MFI (ML‐MFI) zeolite. ML‐MFI was first exfoliated by melt compounding and then detemplated by treatment with a mixture of H2SO4 and H2O2 (piranha solution). The obtained OSDA‐free MFI nanosheets disperse well in water and can be used for coating applications. Deposits made on porous polybenzimidazole (PBI) supports by simple filtration of these suspensions exhibit an n‐butane/isobutane selectivity of 5.4, with an n‐butane permeance of 3.5×10?7 mol m?2 s?1 Pa?1 (ca. 1000 GPU). 相似文献