全文获取类型
收费全文 | 261篇 |
免费 | 80篇 |
国内免费 | 8篇 |
专业分类
化学 | 307篇 |
晶体学 | 2篇 |
力学 | 1篇 |
综合类 | 1篇 |
数学 | 3篇 |
物理学 | 35篇 |
出版年
2024年 | 2篇 |
2023年 | 9篇 |
2022年 | 26篇 |
2021年 | 32篇 |
2020年 | 29篇 |
2019年 | 10篇 |
2018年 | 9篇 |
2017年 | 5篇 |
2016年 | 27篇 |
2015年 | 23篇 |
2014年 | 33篇 |
2013年 | 26篇 |
2012年 | 19篇 |
2011年 | 24篇 |
2010年 | 14篇 |
2009年 | 19篇 |
2008年 | 10篇 |
2007年 | 8篇 |
2006年 | 1篇 |
2005年 | 7篇 |
2004年 | 2篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 2篇 |
1997年 | 4篇 |
排序方式: 共有349条查询结果,搜索用时 31 毫秒
41.
42.
Nidhi Joshi Anindita Mukhopadhyay Sujit Basak Goutam De Krishnananda Chattopadhyay 《Particle & Particle Systems Characterization》2013,30(8):683-694
The presence of magnetic nanoparticles (NPs) in physiological systems induces toxicity through its effects on mitochondrial function and reactive oxygen species (ROS) imbalance. Magnetic NP induced cytotoxicity has been elaborately evaluated for impending threats, however, a detailed investigation is lacking. It is shown that the interaction of Fe3O4 NPs with cytochrome c can lead to different events based on the NPs to protein ratio, the solution conditions, and the type of surface protection. At low NPs concentration, rapid binding and subsequent electron transfer are the preferred events while at higher concentration slow oxidative modification of the protein is initiated. The slow event of protein modification yields conformational disorientation, loss of stability, and formation of amyloid‐like structures with cytochrome c. The possibility that the NP induced oxidative stress and age can work in concert to compromise different aspects of cellular quality control processes is discussed. Suitable surface modifications of the NPs inhibit their direct binding to the protein molecules and minimize NP induced toxicity. 相似文献
43.
H. Eugene Stanley 《Pramana》2005,64(5):645-660
One challenge of biology, medicine, and economics is that the systems treated by these sciences have no perfect metronome
in time and no perfect spatial architecture-crystalline or otherwise. Nonetheless, as if by magic, out of nothing but randomness
one finds remarkably fine-tuned processes in time and remarkably fine-tuned structures in space. To understand this ‘miracle’,
one might consider placing aside the human tendency to see the universe as a machine. Instead, one might address the challenge
of uncovering how, through randomness (albeit, as we shall see, strongly correlated randomness), one can arrive at many spatial
and temporal patterns in biology, medicine, and economics. Inspired by principles developed by statistical physics over the
past 50 years-scale invariance and universality-we review some recent applications of correlated randomness to fields that
might startle Boltzmann if he were alive today. 相似文献
44.
Ciuculescu ED Mekmouche Y Faller P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(3):903-909
Amyloid precursor protein (APP) plays a key role in Alzheimer's disease (AD), although the function of this membrane protein is still unclear. Metal ions are implicated in AD and they also interact with APP. APP possesses a strong ZnII binding site, which is evolutionary conserved. In this paper a synthetic peptide, APP170-188, with a sequence corresponding to the conserved ZnII-binding domain of APP, was synthesised and its metal-binding properties analysed. Titration experiments pointed to the binding of a stoichiometric amount of divalent ions. Further studies indicated that the binding of divalent metals like ZnII, CdII and CoII induces the dimerisation of the peptide. This dimer contains a dinuclear cluster in which the two divalent metals are bridged by two thiolate ligands from cysteine residues. The other two ligands of the tetrahedral coordination sites of each metal ion are terminal thiolate ligands. This structure was supported by the following arguments. The complex formed with CoII presents the characteristic features for tetrahedral tetrathiolate coordination in its UV-visible spectrum. The sequence of APP170-188 contains only three cysteine residues, which is incompatible with a monomeric CoII-APP170-188 complex. EPR measurements of the complex with one equivalent of CoII show almost no signal at 4 K, which is compatible with an antiferromagnetic spin-coupling of the metal ions in a cluster structure. Size-exclusion chromatography indicated that the elution time for the complexes with ZnII and CdII corresponds to the expected molecular weight of a dimer. The circular dichroism (CD) spectrum of the complex with one equivalent of CdII shows a band at 265 nm+, and an ellipticity similar to those observed for similar CdII-thiolate clusters. Possible biological implications of the ZnII binding site and the metal-induced dimerisation are discussed. 相似文献
45.
Kazuyuki Akasaka 《高压研究》2013,33(4):453-457
NMR experiments at variable pressure reveal a wide range of conformation of a globular protein spanning from within the folded ensemble to the fully unfolded ensemble, herewith collectively called “high-energy conformers”. The observation of “high-energy conformers” in a wide variety of globular proteins has led to the “volume theorem”: the partial molar volume of a protein decreases with the decrease in its conformational order. Since “high-energy conformers” are intrinsically more reactive than the basic folded conformer, they could play decisive roles in all phenomena of proteins, namely function, environmental adaptation and misfolding. Based on the information on high-energy conformers and the rules on their partial volume in its monomeric state and amyloidosis, one may have a general view on what is happening on proteins under pressure. Moreover, one may even choose a high-energy conformer of a protein with pressure as variable for a particular purpose. Bridging “high-energy conformers” to macroscopic pressure effects could be a key to success in pressure application to biology, medicine, food technology and industry in the near future. 相似文献
46.
Haeun Song Yoonyoung Kim Inkyu Kim Young‐Kwan Kim Sunbum Kwon Kyungtae Kang 《化学:亚洲杂志》2020,15(1):91-97
The properties of eumelanin‐like particles (EMPs) and pheomelanin‐like particles (PMPs) in regulating the process of amyloid formation of amyloid‐beta 42 (Aβ42) were examined. EMPs and PMPs are effective both in interfering with amyloid aggregation of Aβ42 and in remodeling matured Αβ42 fibers. The results suggest that some (but not all) molecular species consisting of melanin‐like particles (MPs) are responsible for their inhibiting property toward amyloid formation, and the influence is likely manifested by long‐range interactions. Incubating preformed Aβ42 fibers with catechols or MPs leads to the formation of mesh‐like, interconnected Aβ42 fibers encapsulated with melanin‐like material. MPs are kinetically more effective than catechol monomers in this process, and a detailed investigation reveals that 4,5‐dihydroxyindole, a major intermediate in the formation of melanin‐like species, and its derivatives are mainly responsible for remodeling amyloid fibers. 相似文献
47.
Dr. Gao Li Wu-Yue Yang Wen-Hao Li Yun-Yi Luo Yeh-Jun Lim Prof. Dr. Yang Li Dr. Ashim Paul Prof. Dr. Daniel Segal Liu Hong Prof. Dr. Yan-Mei Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(16):3499-3503
It has been reported that many molecules could inhibit the aggregation of Aβ (amyloid-β) through suppressing either primary nucleation, secondary nucleation, or elongation processes. In order to suppress multiple pathways of Aβ aggregation, we screened 23 small molecules and found two types of inhibitors with different inhibiting mechanisms based on chemical kinetics analysis. Trp-glucose conjugates ( AS2 ) could bind with fibril ends while natural products ( D3 and D4 ) could associate with monomers. A cocktail of these two kinds of molecules achieved co-inhibition of various fibrillar species and avoid unwanted interference. 相似文献
48.
Enrico Falcone Ikhlas M. M. Ahmed Dr. Valentina Oliveri Dr. Francesco Bellia Dr. Bertrand Vileno Dr. Youssef El Khoury Prof. Petra Hellwig Prof. Peter Faller Prof. Graziella Vecchio 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(8):1871-1879
Mounting evidence supports the role of amyloidogenesis, oxidative stress, and metal dyshomeostasis in the development of neurodegenerative disorders. Parkinson's Disease is characterized by α-synuclein (αSyn) accumulation and aggregation in brain regions, also promoted by Cu2+. αSyn is modified by reactive carbonyl species, including acrolein (ACR). Notwithstanding these findings, the interplay between ACR, copper, and αSyn has never been investigated. Therefore, we explored more thoroughly the effects of ACR on αSyn using an approach based on LC-MS/MS analysis. We also evaluated the influence of Cu2+ on the protein carbonylation and how the ACR modification impacts the Cu2+ binding and the production of Reactive Oxygen Species (ROS). Finally, we investigated the effects of ACR and Cu2+ ions on the αSyn aggregation by dynamic light scattering and fluorescence assays. Cu2+ regioselectively inhibits the modification of His50 by ACR, the carbonylation lowers the affinity of His50 for Cu2+ and ACR inhibits αSyn aggregation both in the presence and in the absence of Cu2+. 相似文献
49.
Interaction of PiB‐Derivative Metal Complexes with Beta‐Amyloid Peptides: Selective Recognition of the Aggregated Forms
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. André F. Martins David M. Dias Dr. Jean‐François Morfin Dr. Sara Lacerda Dr. Douglas V. Laurents Dr. Éva Tóth Prof. Carlos F. G. C. Geraldes 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(14):5413-5422
Metal complexes are increasingly explored as imaging probes in amyloid peptide related pathologies. We report the first detailed study on the mechanism of interaction between a metal complex and both the monomer and the aggregated form of Aβ1–40 peptide. We have studied lanthanide(III) chelates of two PiB‐derivative ligands (PiB=Pittsburgh compound B), L1 and L2, differing in the length of the spacer between the metal‐complexing DO3A macrocycle (DO3A= 1,4,7,10‐tetraazacyclododecane‐1,4,7‐triacetic acid) and the peptide‐recognition PiB moiety. Surface plasmon resonance (SPR) and saturation transfer difference (STD) NMR spectroscopy revealed that they both bind to aggregated Aβ1–40 (KD=67–160 μM ), primarily through the benzothiazole unit. HSQC NMR spectroscopy on the 15N‐labeled, monomer Aβ1–40 peptide indicates nonsignificant interaction with monomeric Aβ. Time‐dependent circular dichroism (CD), dynamic light scattering (DLS), and TEM investigations of the secondary structure and of the aggregation of Aβ1–40 in the presence of increasing amounts of the metal complexes provide coherent data showing that, despite their structural similarity, the two complexes affect Aβ fibril formation distinctly. Whereas GdL1, at higher concentrations, stabilizes β‐sheets, GdL2 prevents aggregation by promoting α‐helical structures. These results give insight into the behavior of amyloid‐targeted metal complexes in general and contribute to a more rational design of metal‐based diagnostic and therapeutic agents for amyloid‐ associated pathologies. 相似文献
50.
Back Cover: Co‐existence of Two Different α‐Synuclein Oligomers with Different Core Structures Determined by Hydrogen/Deuterium Exchange Mass Spectrometry (Angew. Chem. Int. Ed. 29/2014)
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)