全文获取类型
收费全文 | 711篇 |
免费 | 21篇 |
国内免费 | 2篇 |
专业分类
化学 | 327篇 |
晶体学 | 1篇 |
力学 | 75篇 |
数学 | 172篇 |
物理学 | 159篇 |
出版年
2023年 | 11篇 |
2022年 | 12篇 |
2021年 | 27篇 |
2020年 | 19篇 |
2019年 | 15篇 |
2018年 | 23篇 |
2017年 | 20篇 |
2016年 | 36篇 |
2015年 | 22篇 |
2014年 | 20篇 |
2013年 | 46篇 |
2012年 | 28篇 |
2011年 | 30篇 |
2010年 | 23篇 |
2009年 | 20篇 |
2008年 | 34篇 |
2007年 | 26篇 |
2006年 | 29篇 |
2005年 | 24篇 |
2004年 | 25篇 |
2003年 | 10篇 |
2002年 | 13篇 |
2001年 | 7篇 |
2000年 | 7篇 |
1999年 | 9篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 9篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1984年 | 4篇 |
1981年 | 4篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1974年 | 6篇 |
1973年 | 4篇 |
1970年 | 7篇 |
1969年 | 5篇 |
1968年 | 5篇 |
1931年 | 4篇 |
1927年 | 3篇 |
1890年 | 3篇 |
1889年 | 3篇 |
1870年 | 4篇 |
排序方式: 共有734条查询结果,搜索用时 15 毫秒
561.
562.
Galvan Giulio Sciandrone Marco Lucidi Stefano 《Computational Optimization and Applications》2021,80(1):33-53
Computational Optimization and Applications - In the present paper we propose to rewrite a nonsmooth problem subjected to convex constraints as an unconstrained problem. We show that this novel... 相似文献
563.
Dr. Erica Del Grosso Irene Ponzo Dr. Giulio Ragazzon Prof. Leonard J. Prins Prof. Francesco Ricci 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21244-21249
Nature employs sulfur switches, that is, redox-active disulfides, to kinetically control biological pathways in a highly efficient and reversible way. Inspired by this mechanism, we describe herein a DNA-based synthetic nanodevice that acts as a sulfur switch and can be temporally controlled though redox regulation. To do this, we rationally designed disulfide DNA strands (modulators) that hybridize to a ligand-binding DNA nanodevice and act as redox-active allosteric regulators inducing the nanodevice to release or load its ligand. Upon reduction, the allosteric modulator spontaneously de-hybridizes from the nanodevice and, as a result, its effect is transient. The system is reversible and has an unprecedented high tolerance to waste products and displays transient behavior for over 40 cycles without significant loss of efficiency. Kinetic control of DNA-based ligand-binding nanodevices through purely chemical reactions paves the way for temporal regulation of more complex chemical pathways. 相似文献
564.
Dr. Giulio Bertuzzi Dr. David McLeod Dr. Lisa-Marie Mohr Prof. Dr. Karl Anker Jørgensen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(67):15491-15496
A highly stereoselective 1,3-dipolar [6+4] cycloaddition towards bridged azabicyclo[4.3.1]decane scaffolds has been developed, reacting aldehydes, 2-aminomalonates and tropone under mild conditions in the presence of a chiral phosphoric acid catalyst. The scope is demonstrated for a series of aldehydes and 2-aminomalonates, and the reaction proceeds in high yields, >95:5 d.r. and up to 99 % ee. A series of transformations, as well as a mechanistic proposal, are presented. 相似文献
565.
Danielle Cristina Teles-Ferreira Dr. Irene Conti Dr. Rocío Borrego-Varillas Dr. Artur Nenov Dr. Ivo H. M. Van Stokkum Dr. Lucia Ganzer Dr. Cristian Manzoni Dr. Ana Maria de Paula Prof. Giulio Cerullo Prof. Marco Garavelli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(1):336-343
Photoinduced processes in thiouracil derivatives have lately attracted considerable attention due to their suitability for innovative biological and pharmacological applications. Here, sub-20 fs broadband transient absorption spectroscopy in the near-UV are combined with CASPT2/MM decay path calculations to unravel the excited-state decay channels of water solvated 2-thio and 2,4-dithiouracil. These molecules feature linear absorption spectra with overlapping ππ* bands, leading to parallel decay routes which we systematically track for the first time. The results reveal that different processes lead to the triplet states population, both directly from the ππ* absorbing state and via the intermediate nπ* dark state. Moreover, the 2,4-dithiouracil decay pathways is shown to be strongly correlated either to those of 2- or 4-thiouracil, depending on the sulfur atom on which the electronic transition localizes. 相似文献
566.
Lorenzo Lombardi Alessandro Kovtun Sebastiano Mantovani Dr. Giulio Bertuzzi Laura Favaretto Cristian Bettini Dr. Vincenzo Palermo Dr. Manuela Melucci Prof. Marco Bandini 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(26):e202200333
We present an environmentally benign methodology for the covalent functionalization (arylation) of reduced graphene oxide (rGO) nanosheets with arylazo sulfones. A variety of tagged aryl units were conveniently accommodated at the rGO surface via visible-light irradiation of suspensions of carbon nanostructured materials in aqueous media. Mild reaction conditions, absence of photosensitizers, functional group tolerance and high atomic fractions (XPS analysis) represent some of the salient features characterizing the present methodology. Control experiments for the mechanistic elucidation (Raman analysis) and chemical nanomanipulation of the tagged rGO surfaces are also reported. 相似文献
567.
Dr. Julie Pham Dr. Alvaro Hernandez Dr. Anna Cioce Dr. Silvia Achilli Dr. Giulio Goti Dr. Corinne Vivès Dr. Michel Thepaut Prof. Dr. Anna Bernardi Prof. Dr. Franck Fieschi Dr. Niels-Christian Reichardt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(56):12818-12830
Due to their interactions with C-type lectin receptors (CLRs), glycans from the helminth Schistosoma mansoni represent promising leads for treatment of autoimmune diseases, allergies or cancer. We chemo-enzymatically synthesized nine O-glycans based on the two predominant O-glycan cores observed in the infectious stages of schistosomiasis, the mucin core 2 and the S. mansoni core. The O-glycans were fucosylated next to a selection of N-glycans directly on a microarray slide using a recombinant fucosyltransferase and GDP-fucose or GDP-6-azidofucose as donor. Binding assays with fluorescently labelled human CLRs DC-SIGN, DC-SIGNR and MGL revealed the novel O-glycan O8 as the best ligand for MGL from our panel. Significant binding to DC-SIGN was also found for azido-fucosylated glycans. Contrasting binding specificities were observed between the monovalent carbohydrate recognition domain (CRD) and the tetravalent extracellular domain (ECD) of DC-SIGNR. 相似文献
568.
Giulio A. Amadei Choi‐Fong Cho John D. Lewis Leonard G. Luyt 《Journal of mass spectrometry : JMS》2010,45(3):241-251
A novel approach to high‐throughput sequence deconvolution of on‐bead small peptides (MW < 2000 Da) using on‐target MALDI‐TOF/TOF instrumentation is presented. Short peptides of pentamer and octamer length, covalently attached to TentaGel polystyrene beads through a photolabile linker, were placed onto the MALDI target, apportioned with suitable matrix (2,5‐dihydroxybenzoic acid) and then hit with the instrument laser (Nd : YAG, 355 nm). This induced easy and highly reproducible photochemical cleavage, desorption (MS mode) and fragmentation (MS/MS mode). Peptide fragments were identified with a mass accuracy of 0.1 Da of the expected values. This technique significantly accelerates the sequence determination of positive peptide hits obtained from random combinatorial libraries when screening against biological targets, paving the way for a rapid and efficient method to identify molecular imaging ligands specific to pathological targets in cancer and other diseases. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
569.
We consider the question of thermalization for isolated quantum systems after a sudden parameter change, a so-called quantum quench. In particular, we investigate the prerequisites for thermalization, focusing on the statistical properties of the time-averaged density matrix and of the expectation values of observables in the final eigenstates. We find that eigenstates, which are rare compared to the typical ones sampled by the microcanonical distribution, are responsible for the absence of thermalization of some infinite integrable models and play an important role for some nonintegrable systems of finite size, such as the Bose-Hubbard model. We stress the importance of finite size effects for the thermalization of isolated quantum systems and discuss two scenarios for thermalization. 相似文献
570.
Giulio Tiozzo 《中国科学 数学(英文版)》2018,61(12):2299-2310
We consider the topological entropy h(θ) of real unimodal maps as a function of the kneading parameter θ (equivalently, as a function of the external angle in the Mandelbrot set). We prove that this function is locally Hölder continuous where h(θ) > 0, and more precisely for any θ which does not lie in a plateau the local Hölder exponent equals exactly, up to a factor log 2, the value of the function at that point. This confirms a conjecture of Isola and Politi (1990), and extends a similar result for the dimension of invariant subsets of the circle. 相似文献