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961.
Towards a Sustainable Synthesis of Formate Salts: Combined Catalytic Methanol Dehydrogenation and Bicarbonate Hydrogenation 下载免费PDF全文
Dr. Qiang Liu Lipeng Wu Dr. Samet Gülak Dr. Nils Rockstroh Dr. Ralf Jackstell Prof. Dr. Matthias Beller 《Angewandte Chemie (International ed. in English)》2014,53(27):7085-7088
Formate salts are important chemicals widely used in everyday products. The current industrial‐scale manufacture of formates requires CO at high pressure and harsh reaction conditions. Herein, we describe a new process for these products without the utilization of hazardous gases and chemicals. By application of ruthenium pincer complexes, a simultaneous methanol dehydrogenation and bicarbonate hydrogenation reaction proceeds, which provides a green synthesis of formate salts with excellent TON (>18 000), TOF (>1300 h?1), and yield (>90 %). 相似文献
962.
Peptide‐Templated Acyl Transfer: A Chemical Method for the Labeling of Membrane Proteins on Live Cells 下载免费PDF全文
Ulrike Reinhardt Jonathan Lotze Sarah Zernia Dr. Karin Mörl Prof. Dr. Annette G. Beck‐Sickinger Prof. Dr. Oliver Seitz 《Angewandte Chemie (International ed. in English)》2014,53(38):10237-10241
The development of a method is described for the chemical labeling of proteins which occurs with high target specificity, proceeds within seconds to minutes, and offers a free choice of the reporter group. The method relies upon the use of peptide templates, which align a thioester and an N‐terminal cysteinyl residue such that an acyl transfer reaction is facilitated at nanomolar concentrations. The protein of interest is N‐terminally tagged with a 22 aa long Cys‐E3 peptide (acceptor), which is capable of forming a coiled‐coil with a reporter‐armed K3 peptide (donor). This triggers the transfer of the reporter to the acceptor on the target protein. Because ligation of the two interacting peptides is avoided, the mass increase at the protein of interest is minimal. The method is exemplified by the rapid fluorescent labeling and fluorescence microscopic imaging of the human Y2 receptor on living cells. 相似文献
963.
Dr. Dorian S. N. Parker Prof. Ralf I. Kaiser Dr. Tyler P. Troy Dr. Musahid Ahmed 《Angewandte Chemie (International ed. in English)》2014,53(30):7740-7744
For almost half a century, polycyclic aromatic hydrocarbons (PAHs) have been proposed to play a key role in the astrochemical evolution of the interstellar medium (ISM) and in the chemistry of combustion systems. However, even the most fundamental reaction mechanism assumed to lead to the simplest PAH naphthalene—the hydrogen abstraction–acetylene addition (HACA) mechanism—has eluded experimental observation. Here, by probing the phenylacetylene (C8H6) intermediate together with naphthalene (C10H8) under combustion‐like conditions by photo‐ionization mass spectrometry, the very first direct experimental evidence for the validity of the HACA mechanism which so far had only been speculated theoretically is reported. 相似文献
964.
Dr. Sebastian Götze Dr. Nahid Azzouz Dr. Yu‐Hsuan Tsai Prof. Dr. Uwe Groß Anika Reinhardt Dr. Chakkumkal Anish Prof. Dr. Peter H. Seeberger Dr. Daniel Varón Silva 《Angewandte Chemie (International ed. in English)》2014,53(50):13701-13705
Around 2 billion people worldwide are infected with the apicomplexan parasite Toxoplasma gondii which induces a variety of medical conditions. For example, primary infection during pregnancy can result in fetal death or mental retardation of the child. Diagnosis of acute infections in pregnant women is challenging but crucially important as the drugs used to treat T. gondii infections are potentially harmful to the unborn child. Better, faster, more reliable, and cheaper means of diagnosis by using defined antigens for accurate serological tests are highly desirable. Synthetic pathogen‐specific glycosylphosphatidylinositol (GPI) glycan antigens are diagnostic markers and have been used to distinguish between toxoplasmosis disease states using human sera. 相似文献
965.
Inside Cover: Volatile Times for the Very First Ionic Liquid: Understanding the Vapor Pressures and Enthalpies of Vaporization of Ethylammonium Nitrate (Chem. Eur. J. 37/2014) 下载免费PDF全文
966.
Development of a Ruthenium/Phosphite Catalyst System for Domino Hydroformylation–Reduction of Olefins with Carbon Dioxide 下载免费PDF全文
Dr. Qiang Liu Lipeng Wu Dr. Ivana Fleischer Dr. Detlef Selent Prof. Dr. Robert Franke Dr. Ralf Jackstell Prof. Dr. Matthias Beller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(23):6888-6894
An efficient domino ruthenium‐catalyzed reverse water‐gas‐shift (RWGS)‐hydroformylation‐reduction reaction of olefins to alcohols is reported. Key to success is the use of specific bulky phosphite ligands and triruthenium dodecacarbonyl as the catalyst. Compared to the known ruthenium/chloride system, the new catalyst allows for a more efficient hydrohydroxymethylation of terminal and internal olefins with carbon dioxide at lower temperature. Unwanted hydrogenation of the substrate is prevented. Preliminary mechanism investigations uncovered the homogeneous nature of the active catalyst and the influence of the ligand and additive in individual steps of the reaction sequence. 相似文献
967.
Carolin Schaab Ralf Christian Kling Jürgen Einsiedel Harald Hübner Tim Clark Dieter Seebach Peter Gmeiner 《ChemistryOpen》2014,3(5):206-218
Subtype-selective agonists of the neurotensin receptor NTS2 represent a promising option for the treatment of neuropathic pain, as NTS2 is involved in the mediation of μ-opioid-independent anti-nociceptive effects. Based on the crystal structure of the subtype NTS1 and previous structure–activity relationships (SARs) indicating a potential role for the sub-pocket around Tyr11 of NT(8–13) in subtype-specific ligand recognition, we have developed new NTS2-selective ligands. Starting from NT(8–13), we replaced the tyrosine unit by β2-amino acids (type 1), by heterocyclic tyrosine bioisosteres (type 2) and peptoid analogues (type 3). We were able to evolve an asymmetric synthesis of a 5-substituted azaindolylalanine and its application as a bioisostere of tyrosine capable of enhancing NTS2 selectivity. The S-configured test compound 2 a, [(S)-3-(pyrazolo[1,5-a]pyridine-5-yl)-propionyl11]NT(8–13), exhibits substantial NTS2 affinity (4.8 nm) and has a nearly 30-fold NTS2 selectivity over NTS1. The (R)-epimer 2 b showed lower NTS2 affinity but more than 600-fold selectivity over NTS1. 相似文献
968.
969.
970.
Thomas Gerstner Markus Holtz Ralf Goschnick 《Insurance: Mathematics and Economics》2008,42(2):704-716
New regulations and a stronger competition have increased the importance of stochastic asset-liability management (ALM) models for insurance companies in recent years. In this paper, we propose a discrete time ALM model for the simulation of simplified balance sheets of life insurance products. The model incorporates the most important life insurance product characteristics, the surrender of contracts, a reserve-dependent bonus declaration, a dynamic asset allocation and a two-factor stochastic capital market. All terms arising in the model can be calculated recursively which allows an easy implementation and efficient simulation. Furthermore, the model is designed to have a modular organization which permits straightforward modifications and extensions to handle specific requirements. In a sensitivity analysis for sample portfolios and parameters, we investigate the impact of the most important product and management parameters on the risk exposure of the insurance company and show that the model captures the main behaviour patterns of the balance sheet development of life insurance products. 相似文献