全文获取类型
收费全文 | 424篇 |
免费 | 10篇 |
国内免费 | 4篇 |
专业分类
化学 | 246篇 |
晶体学 | 11篇 |
力学 | 8篇 |
数学 | 47篇 |
物理学 | 126篇 |
出版年
2024年 | 4篇 |
2023年 | 3篇 |
2022年 | 13篇 |
2021年 | 6篇 |
2020年 | 8篇 |
2019年 | 20篇 |
2018年 | 12篇 |
2017年 | 13篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 9篇 |
2013年 | 21篇 |
2012年 | 33篇 |
2011年 | 25篇 |
2010年 | 15篇 |
2009年 | 10篇 |
2008年 | 12篇 |
2007年 | 13篇 |
2006年 | 21篇 |
2005年 | 15篇 |
2004年 | 8篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1983年 | 6篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 7篇 |
1962年 | 2篇 |
排序方式: 共有438条查询结果,搜索用时 109 毫秒
181.
We report results of a study of (integer) quantum Hall transitions in a single or multiple Landau levels for non-interacting
electrons in disordered two-dimensional systems, obtained by projecting a tight-binding Hamiltonian to the corresponding magnetic
subbands. In finite-size systems, we find that mesoscopic effects often dominate, leading to apparent non-universal scaling
behavior in higher Landau levels. This is because localization length, which grows exponentially with Landau level index,
exceeds the system sizes amenable to the numerical study at present. When band mixing between multiple Landau levels is present,
mesoscopic effects cause a crossover from a sequence of quantum Hall transitions for weak disorder to classical behavior for
strong disorder. This behavior may be of relevance to experimentally observed transitions between quantum Hall states and
the insulating phase at low magnetic fields. 相似文献
182.
LetA
e
be the algebra obtained by adjoining identity to a non-unital Banach algebra (A, ∥ · ∥). Unlike the case for aC*-norm on a Banach *-algebra,A
e
admits exactly one uniform norm (not necessarily complete) if so doesA. This is used to show that the spectral extension property carries over fromA to A
e
. Norms onA
e
that extend the given complete norm ∥ · ∥ onA are investigated. The operator seminorm ∥ · ∥op onA
e
defined by ∥ · ∥ is a norm (resp. a complete norm) iffA has trivial left annihilator (resp. ∥ · ∥op restricted toA is equivalent to ∥ · ∥). 相似文献
183.
Bhatt KH Grego S Velev OD 《Langmuir : the ACS journal of surfaces and colloids》2005,21(14):6603-6612
We report an electrohydrodynamic effect arising from the application of alternating electric fields to patterned electrode surfaces. The AC fields were applied to dilute suspensions of latex microspheres enclosed between a patterned silicon wafer and an ITO-coated glass slide in a small chamber. The latex particles became collected in the center of the conductive "corrals" on the silicon wafer acting as bottom electrode. The particle collection efficiency and speed depended only on the frequency and strength of the field and were independent of the material properties of the particles or the electrodes. The leading effect in the particle collection process is AC electrohydrodynamics. We discuss how the electrohydrodynamic flows emerge from the spatially nonuniform field and interpret the experimental results by means of electrostatic and hydrodynamic simulations. The technique allows three-dimensional microfluidic pumping and transport by the use of two-dimensional patterns. We demonstrate on-chip collection of latex particles, yeast cells, and microbes. 相似文献
184.
The pH vs. fluorescence intensity profiles for a number of tetracyclines are investigated. Fluorescence is obtained in alkaline solutions and is associated with the ionized form of the phenolic-β-diketone site of these molecules. The shape of the pH vs. fluorescence intensity profiles is best explained by representing the acid-base equilibria in solution by a micro-ionization scheme. In combination with measurements made on model compounds in which the dimethylammonium site was either blocked or removed, it proved possible to estimate values for the micro-ionization constants in aqueous solution; pk13 values of 7.82, 7.85 and 7.04 were obtained for tetracycline, oxytetracycline and demethylchlortetracyline, respectively. 相似文献
185.
186.
M.Vivekananda Bhatt 《Journal of organometallic chemistry》1978,156(1):221-226
In methylene chloride solution, B-bromo-9-borabicyclo[3.3.1]nonane (BBr-9-BBN) readily cleaves, in excellent yield, a variety of ethers of representative structural types. The reagent can also be used for selective cleavage of one of the ether groups in a molecule containing more than one such group. 相似文献
187.
Sharma Neeraj Sood Anoop K. Bhatt Sarvjeet S. Kalia Shashi B. Chaudhry Subhash C. 《Transition Metal Chemistry》1998,23(5):557-560
Complexes of composition [VCl(acac)2(OAr1–4)] and [V(acac)2(OAr1–4)2] (HOAr1=HOC6H4NO2–4, HOAr2= HOC6H4OMe-4, HOAr3=HOC6H4But-4 and HOAr4= HOC6H2But-2,6–Me-4; acac=2,4–pentanedionato ion) have been synthesized by the reaction of [VCl2(acac)2] with the respective phenols or their trimethylsilyl derivatives. The complexes have been characterized by physicochemical and spectroscopic techniques. They are non-electrolytes in nitrobenzene. Room temperature magnetic moments in the 1.71–1.82B range are consistent with the VIV system. The reactions of [VCl(acac)2(OAr2)] and [VCl(acac)2(OAr3)] with chloride acceptors have been studied by conductance techniques and the formation of ionic complexes of the types [V(acac)2(OAr2,3)][MCl4] (M=Fe, Al or Sb) and [V(acac)2(OAr2,3)][MCl6] (M=P or Sb) is indicated by the conductance composition curves. Several of these complexes have been isolated and characterized. 相似文献
188.
189.
190.
Immobilization of the Gas Signaling Molecule H2S by Radioisotopes: Detection,Quantification, and In Vivo Imaging
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)
Woonghee Lee Min Hwan Kim Phuong Tu Huynh Heesu Ahn Dr. Nikunj Bhatt Dr. Yong Jin Lee Dr. Jung Young Kim Prof. Kwon Moo Park Prof. Isao Ishii Prof. Shin‐Geol Kang Prof. Jeongsoo Yoo 《Angewandte Chemie (International ed. in English)》2016,55(32):9365-9370
Hydrogen sulfide (H2S) has multifunctional roles as a gas signaling molecule in living systems. However, the efficient detection and imaging of H2S in live animals is very challenging. Herein, we report the first radioisotope‐based immobilization technique for the detection, quantification, and in vivo imaging of endogenous H2S. Macrocyclic 64Cu complexes that instantly reacted with gaseous H2S to form insoluble 64CuS in a highly sensitive and selective manner were prepared. The H2S concentration in biological samples was measured by a thin‐layer radiochromatography method. When 64Cu–cyclen was injected into mice, an elevated H2S concentration in the inflamed paw was clearly visualized and quantified by Cerenkov luminescence and positron emission tomography (PET) imaging. PET imaging was also able to pinpoint increased H2S levels in a millimeter‐sized infarcted lesion of the rat heart. 相似文献