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1.
Alexandru Vlasceanu Dr. Søren L. Broman Anne S. Hansen Anders B. Skov Prof. Dr. Martina Cacciarini Prof. Dr. Anders Kadziola Prof. Dr. Henrik G. Kjaergaard Prof. Dr. Kurt V. Mikkelsen Prof. Dr. Mogens Brøndsted Nielsen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(31):10796-10800
The conversion and efficient storage of solar energy is recognized to hold significant potential with regard to future energy solutions. Molecular solar thermal batteries based on photochromic systems exemplify one possible technology able to harness and apply this potential. Herein is described the synthesis of a macrocycle based on a dimer of the dihydroazulene/vinylheptafulvene (DHA/VHF) photo/thermal couple. By taking advantage of conformational strain, this DHA–DHA macrocycle presents an improved ability to absorb and store incident light energy in chemical bonds (VHF–VHF). A stepwise energy release over two sequential ring‐closing reactions (VHF→DHA) combines the advantages of an initially fast discharge, hypothetically addressing immediate energy consumption needs, followed by a slow process for consistent, long‐term use. This exemplifies another step forward in the molecular engineering and design of functional organic materials towards solar thermal energy storage and release. 相似文献
2.
Renewability is not Enough: Recent Advances in the Sustainable Synthesis of Biomass‐Derived Monomers and Polymers 下载免费PDF全文
Dr. Audrey Llevot Patrick‐Kurt Dannecker Marc von Czapiewski Lena C. Over Zafer Söyler Prof. Dr. Michael A. R. Meier 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(33):11510-11521
Taking advantage of the structural diversity of different biomass resources, recent efforts were directed towards the synthesis of renewable monomers and polymers, either for the substitution of petroleum‐based resources or for the design of novel polymers. Not only the use of biomass, but also the development of sustainable chemical approaches is a crucial aspect for the production of sustainable materials. This review discusses the recent examples of chemical modifications and polymerizations of abundant biomass resources with a clear focus on the sustainability of the described processes. Topics such as synthetic methodology, catalysis, and development of new solvent systems or greener alternative reagents are addressed. The chemistry of vegetable oil derivatives, terpenes, lignin, carbohydrates, and sugar‐based platform chemicals was selected to highlight the trends in the active field of a sustainable use of renewable resources. 相似文献
3.
Jieping Wang Norbert Moszner Kurt Dietliker Hansjörg Grützmacher Robert Liska 《Journal of polymer science. Part A, Polymer chemistry》2016,54(4):473-479
The monoacylphosphineoxide (MAPO) salts Na‐TPO and Li‐TPO and the bisacylphosphineoxide (BAPO) salts BAPO‐ONa and BAPO‐OLi define an important and in the latter case a new class of water‐soluble photoinitiators (PIs) for radical polymerization. These compounds showed excellent water‐solubility of at least 29 g/L for Na‐TPO and up to 60 g/L for BAPO‐ONa in deionized water, thus exceeding the solubility of the state of the art PI for water‐based systems Irgacure 2959 ( I2959 ) 6‐ to 12‐fold. However, biocompatibility, storage stability, and reactivity were equally important to replace the state of the art compounds. Concerning these properties, the MAPO and BAPO salts were at least in the same range (biocompatibility, stability) or showed even better results (reactivity) and had the additional advantage of visible light initiation. Na‐TPO and Li‐TPO achieved double bond conversions of an aqueous solution of N‐acryloylmorpholine over 97% with broad band irradiation (320–500 nm), Li‐TPO showed additionally very good biocompatibility (LC50 = 3.1 mmol/L) and BAPO‐OLi showed highest reactivity with visible light irradiation. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 473–479 相似文献
4.
Dr. Wan-Shan Li Dr. Ren-Jie Yan Yi Yu Prof. Zhi Shi Dr. Attila Mándi Dr. Li Shen Prof. Tibor Kurtán Prof. Jun Wu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(31):13128-13136
Marine dinoflagellates produce remarkable organic molecules, particularly those with polyoxygenated long-carbon-chain backbones, namely super-carbon-chain compounds (SCCCs), characterized by the presence of numerous stereogenic carbon centers on acyclic polyol carbon chains. Even today, it is a challenge to determine the absolute configurations of these compounds. In this work, the planar structures and absolute configurations of two highly flexible SCCCs, featuring either a C69- or C71-linear carbon backbone, gibbosols A and B, respectively, each containing thirty-seven stereogenic carbon centers, were unambiguously established by a combined chemical, spectroscopic, and computational approach. The discovery of gibbosols A and B with two hydrophilic acyclic polyol chains represents an unprecedented class of SCCCs. A reasonable convergent strategy for the biosynthesis of these SCCCs was proposed. 相似文献
5.
Simple,Rapid and Sensitive Electrochemical Method for the Determination of the Triketone Herbicide Sulcotrione in River Water Using a Glassy Carbon Electrode 下载免费PDF全文
We report a novel, simple, rapid and sensitive electrochemical method for the determination of sulcotrione, a member of the relatively new class of triketone herbicides, using differential pulse voltammetry on a glassy carbon electrode. Its electrochemical behavior including influences of electrolyte composition, pH and scan rate was studied to select optimal experimental parameters for its determination. In Britton? Robinson buffer at pH 3 sulcotrione provided a well‐defined reduction peak at ?0.84 V (vs. Ag/AgCl electrode), with good repeatability (relative standard deviation of 2.3 % for 8 measurements at 10 µM concentration level). With optimized parameters differential pulse voltammetry rendered two linear concentration ranges from 0.2 to 2 µM and from 2 to 50 µM with a detection limit of 0.05 µM. The proposed procedure was successfully applied to the determination of sulcotrione in spiked river water samples with satisfactory recoveries (93–109 %). The developed method may represent a simple, rapid and sensitive alternative to highly toxic mercury electrodes and chromatographic methods. 相似文献
6.
Copper(I) Clusters with Trifunctional Silyl Amide Ligands. Synthesis and Crystal Structures of [Li(THF)4]2[Cu10{RSi(NPh)3}4] (R = Me,Ph, Vin) 下载免费PDF全文
Treatment of CuCl with the lithiated silyl amides RSi(NLiPh)3 (R = Me, Ph, Vin) in THF as solvent led to the formation of the novel CuI cluster compounds [Li(THF)4]2[Cu10{RSi(NPh)3}4]. For each of the three compounds the X‐ray crystal structure analysis revealed similar Si4N12Cu10 cores which are based on cubane like Cu8 cores bearing two additional peripheral copper atoms. The copper atoms are coordinated nearly linearly by the μ5‐bridging silyl amide ligands with Cu–N distances in the range of 187.1(3) to 194.5(4) pm and N–Cu–N angles of 171.6(1) to 178.7(1)°. For each of the compounds the structural parameters are very similar which indicates that the structures are barely influenced by the different steric requirements of the organic groups bound to silicon. 相似文献
7.
8.
Chuanlei Liu Kurt Ungar Dylan Pierce Ian Hoffman Weihua Zhang 《Journal of Radioanalytical and Nuclear Chemistry》2017,312(3):471-478
In assistance of radionuclide measurements at Canada’s Comprehensive Nuclear-Test-Ban Treaty (CTBT) laboratory, a Geant4 Monte Carlo application has been developed in simulating a broad-energy germanium detector and calculating detection efficiencies. The detector model was optimized in a reliable and non-biased manner through simultaneous tuning on gap distance and detector dimension, and was validated over various realistic measurement scenarios. All work is based on a series of experiments which covers the typical energy range of gamma radiation in environmental analysis, and considers the variety of the CTBT sample type, dimension and distance-to-detector. In all cases, the predicted efficiencies are consistent with the empirical ones within 5%, with a typical deviation of 3% in majority. 相似文献
9.
The thioether functionalized aminosilanes Me2Si(NH‐C6H4‐2‐SR)2 (R = Ph, Me) were lithiated with nBuLi and subsequently reacted with AgCl in the presence of PMe3 or with [AuCl(PMe3)]. In the case of Me2Si(NH‐C6H4‐2‐SPh)2 the dinuclear complexes [M2{Me2Si(NC6H4‐2‐SPh)2}(PMe3)2] (M = Ag; Au) were isolated. The analogous reactions starting from Me2Si(NH‐C6H4‐SMe)2 afforded the dinuclear gold complex [Au2{Me2Si(NC6H4‐2‐SMe)2}(PMe3)2] and the tetranuclear silver complex [Ag4{Me2Si(NC6H4‐2‐SMe)2}2(PMe3)2]. In the dinuclear compounds of the type [M2{Me2Si(NC6H4‐2‐SR)2}(PMe3)2], each of the silylamide N atoms is connected to a M(PMe3) group to give a nearly linear N–M–P arrangement with Ag–N and Au–N bonds in the range of 212.0(4)–213.3(4) pm and 205.3(3)–208.1(9) pm, respectively. [Ag4{Me2Si(NC6H4‐2‐SMe)2}2(PMe3)2] consists of a central Si2N4Ag2 ring with linearly coordinated Ag atoms (Ag‐N: 223.1(4)–222.1(4) pm) and two peripheral Ag(PMe3) units, which are connected to the amido N atoms in a chelating mode. The relatively short transannular Ag ··· Ag separation (277.6(1) pm) within the Si2N4Ag2 ring hints for argentophilic interactions. The peripheral Ag atoms are three coordinated with Ag–N distances of 233.9(4)–242.8(4) pm. 相似文献
10.
We investigate the Frobenius number, genus, type, and minimal presentation of a class of numerical semigroups of embedding dimension 4 of the form \(S = \langle a_1, a_2, a_3, a_4 \rangle \) such that \(a_1 + a_4 = a_2 + a_3\). The investigation focuses on determining the Apery set of S with respect to the multiplicity. 相似文献