全文获取类型
收费全文 | 2093篇 |
免费 | 125篇 |
国内免费 | 13篇 |
专业分类
化学 | 1560篇 |
晶体学 | 10篇 |
力学 | 65篇 |
数学 | 321篇 |
物理学 | 275篇 |
出版年
2024年 | 5篇 |
2023年 | 15篇 |
2022年 | 14篇 |
2021年 | 41篇 |
2020年 | 31篇 |
2019年 | 41篇 |
2018年 | 32篇 |
2017年 | 42篇 |
2016年 | 88篇 |
2015年 | 54篇 |
2014年 | 110篇 |
2013年 | 130篇 |
2012年 | 163篇 |
2011年 | 185篇 |
2010年 | 112篇 |
2009年 | 111篇 |
2008年 | 145篇 |
2007年 | 135篇 |
2006年 | 124篇 |
2005年 | 113篇 |
2004年 | 114篇 |
2003年 | 82篇 |
2002年 | 72篇 |
2001年 | 35篇 |
2000年 | 35篇 |
1999年 | 22篇 |
1998年 | 22篇 |
1997年 | 19篇 |
1996年 | 17篇 |
1995年 | 11篇 |
1994年 | 12篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 17篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1971年 | 2篇 |
1958年 | 2篇 |
排序方式: 共有2231条查询结果,搜索用时 140 毫秒
101.
Craig J. Richmond Roc Matheu Dr. Albert Poater Dr. Laura Falivene Dr. Jordi Benet‐Buchholz Dr. Xavier Sala Prof. Luigi Cavallo Prof. Antoni Llobet 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(52):17282-17286
Extremely slow and extremely fast new water oxidation catalysts based on the Ru–bda (bda=2,2′‐bipyridine‐6,6′‐dicarboxylate) systems are reported with turnover frequencies in the range of 1 and 900 cycles s?1, respectively. Detailed analyses of the main factors involved in the water oxidation reaction have been carried out and are based on a combination of reactivity tests, electrochemical experiments, and DFT calculations. These analyses give a convergent interpretation that generates a solid understanding of the main factors involved in the water oxidation reaction, which in turn allows the design of catalysts with very low energy barriers in all the steps involved in the water oxidation catalytic cycle. We show that for this type of system π‐stacking interactions are the key factors that influence reactivity and by adequately controlling them we can generate exceptionally fast water oxidation catalysts. 相似文献
102.
Multiple Stable Conformations Account for Reversible Concentration‐Dependent Oligomerization and Autoinhibition of a Metamorphic Metallopeptidase 下载免费PDF全文
Mar López‐Pelegrín Dr. Núria Cerdà‐Costa Dr. Anna Cintas‐Pedrola Fátima Herranz‐Trillo Dr. Pau Bernadó Dr. Juan R. Peinado Dr. Joan L. Arolas Prof. Dr. F. Xavier Gomis‐Rüth 《Angewandte Chemie (International ed. in English)》2014,53(40):10624-10630
Molecular plasticity controls enzymatic activity: the native fold of a protein in a given environment is normally unique and at a global free‐energy minimum. Some proteins, however, spontaneously undergo substantial fold switching to reversibly transit between defined conformers, the “metamorphic” proteins. Here, we present a minimal metamorphic, selective, and specific caseinolytic metallopeptidase, selecase, which reversibly transits between several different states of defined three‐dimensional structure, which are associated with loss of enzymatic activity due to autoinhibition. The latter is triggered by sequestering the competent conformation in incompetent but structured dimers, tetramers, and octamers. This system, which is compatible with a discrete multifunnel energy landscape, affords a switch that provides a reversible mechanism of control of catalytic activity unique in nature. 相似文献
103.
Xavier Cattoën Achraf Noureddine Jonas Croissant Nirmalya Moitra Kristýna Bürglová Jana Hodačová Olivia de los Cobos Martine Lejeune Fabrice Rossignol Delphine Toulemon Sylvie Bégin-Colin Benoît P. Pichon Laurence Raehm Jean-Olivier Durand Michel Wong Chi Man 《Journal of Sol-Gel Science and Technology》2014,70(2):245-253
The combination of the copper-catalyzed alkyne-azide cycloaddition (CuAAC) reaction with sol–gel processing enables the versatile preparation of sol–gel materials under different shapes with targeted functionalities through a diversity-oriented approach. In this account, the development of the CuAAC reaction under anhydrous conditions for the synthesis of sol–gel precursors and for the assembling of magnetic nanoparticles on self-assembled monolayers is related, as well as the use of the classical CuAAC methodologies for the functionalization of mesoporous silica nanoparticles and microdots arrays. Coupling CuAAC and Sol–Gel will result in simplified preparations of multifunctional materials with controlled morphologies. 相似文献
104.
Javier Mateos Francesco Rigodanza Alberto Vega‐Pealoza Andrea Sartorel Mirco Natali Tommaso Bortolato Giorgio Pelosi Xavier Company Marcella Bonchio Luca Dell'Amico 《Angewandte Chemie (International ed. in English)》2020,59(3):1302-1312
Twelve naphthochromenone photocatalysts (PCs) were synthesized on gram scale. They absorb across the UV/Vis range and feature an extremely wide redox window (up to 3.22 eV) that is accessible using simple visible light irradiation sources (CFL or LED). Their excited‐state redox potentials, PC*/PC.? (up to 1.65 V) and PC.+/PC* (up to ?1.77 V vs. SCE), are such that these novel PCs can engage in both oxidative and reductive quenching mechanisms with strong thermodynamic requirements. The potential of these bimodal PCs was benchmarked in synthetically relevant photocatalytic processes with extreme thermodynamic requirements. Their ability to efficiently catalyze mechanistically opposite oxidative/reductive photoreactions is a unique feature of these organic photocatalysts, thus representing a decisive advance towards generality, sustainability, and cost efficiency in photocatalysis. 相似文献
105.
Lucie Appy Anaïs Depaix Xavier Bantreil Frédéric Lamaty Suzanne Peyrottes 《Phosphorus, sulfur, and silicon and the related elements》2020,195(11):930-931
AbstractWe have developed original one-pot and protecting group-free approaches, which are also user-friendly and reliable, to synthesize nucleotides and derivatives starting from nucleoside 5’-monophosphates. Both methods present convenient set-up, i.e., non-dry solvents and reagents, substrates in their sodium or acid form, and commercially available and cheap phosphorus reagents as sodium and potassium salts. 相似文献
106.
Siphamandla B. Simelane Monisola I. Ikhile Xavier Y. Mbianda 《Phosphorus, sulfur, and silicon and the related elements》2020,195(7):556-561
AbstractA series of 2-substituted vinylidene-1,1-bisphosphonate esters and their acids were synthesized and tested in vitro for activity against Plasmodium falciparum and Trypanosoma brucei. For each compound, % parasite viability in treated wells was calculated relative to untreated controls for both P. falciparum and T. brucei. Fifty percentage inhibitory concentration (IC50) was also determined for the compounds. Chloroquine and pentamidine were used as positive control drug standards for activity against P. falciparum and T. brucei, respectively. The esters had better antiparasitic activity compared to their corresponding acids. Some of the compounds reduced % parasite viability to as low as 24.3% for P. falciparum and down to 0.602% for T. brucei. Tetraethyl-2-(o-tolyl)-ethene-1,1-bisphosphonate (3b) recorded the best IC50 against T. brucei which was 0.0345?µmol/mL. 相似文献
107.
Ania Alik Chafiaa Bouguechtouli Manon Julien Wolfgang Bermel Rania Ghouil Sophie Zinn‐Justin Francois‐Xavier Theillet 《Angewandte Chemie (International ed. in English)》2020,59(26):10411-10415
Abundant phosphorylation events control the activity of nuclear proteins involved in gene regulation and DNA repair. These occur mostly on disordered regions of proteins, which often contain multiple phosphosites. Comprehensive and quantitative monitoring of phosphorylation reactions is theoretically achievable at a residue‐specific level using 1H‐15N NMR spectroscopy, but is often limited by low signal‐to‐noise at pH>7 and T>293 K. We have developed an improved 13Cα‐13CO correlation NMR experiment that works equally at any pH or temperature, that is, also under conditions at which kinases are active. This allows us to obtain atomic‐resolution information in physiological conditions down to 25 μm . We demonstrate the potential of this approach by monitoring phosphorylation reactions, in the presence of purified kinases or in cell extracts, on a range of previously problematic targets, namely Mdm2, BRCA2, and Oct4. 相似文献
108.
We discuss model-independent constraints on spin observables in exclusive and inclusive reactions, with special attention to the case of photoproduction. 相似文献
109.
110.
Xavier L��pez Pere Mir�� Jorge J. Carb�� Antonio Rodr��guez-Fortea Carles Bo Josep M. Poblet 《Theoretical chemistry accounts》2011,128(4-6):393-404
Computational chemistry applied to the study of polyoxometalates has achieved its maturity in the last years. During two decades, important advances have been made using theoretical tools in the comprehension and interpretation of many relevant issues. In the present mini-review, we want to stress that different techniques have been incorporated to the routine of computation: from the very first Hartree?CFock LCAO-SCF calculation on the decavanadate anion, followed by numerous density functional theory?Cbased studies on increasingly complex systems, also applying correlated ab initio techniques for magnetism and, more recently, using molecular dynamics to analyse properties in liquid media, the information provided by computational chemistry gets more and more relevant. 相似文献