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991.
Zhipeng Jiang Liu Jin Zhilong Han Wei Hu Ziqi Zeng Yulong Sun Jia Xie 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(33):11496-11500
Lithium‐metal anodes are recognized as the most promising next‐generation anodes for high‐energy‐storage batteries. However, lithium dendrites lead to irreversible capacity decay in lithium‐metal batteries (LMBs). Besides, the strict assembly‐environment conditions of LMBs are regarded as a challenge for practical applications. In this study, a workable lithium‐metal anode with an artificial hybrid layer composed of a polymer and an alloy was designed and prepared by a simple chemical‐modification strategy. Treated lithium anodes remained dendrite‐free for over 1000 h in a Li–Li symmetric cell and exhibited outstanding cycle performance in high‐areal‐loading Li–S and Li–LiFePO4 full cells. Moreover, the treated lithium showed improved moisture stability that benefits from the hydrophobicity of the polymer, thus retaining good electrochemical performance after exposure to humid air. 相似文献
992.
Christopher Cooze Raphael Dada Rylan J. Lundgren 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(35):12374-12379
Methods for the addition of unsaturated nucleophiles to carbonyls to generate Z‐olefin products remain rare and often require either alkyl borane or zinc reductants, limiting their utility. Demonstrated here is that formic acid mediates the Rh‐catalyzed, Z‐selective coupling of dienes and aldehydes. The process is distinguished by broad tolerance towards reducible or electrophilic groups. Kinetic analysis suggests that generation of the catalytically active Rh intermediate by ligand dissociation is the rate‐determining step. The rapid generation and trapping of Rh‐allyl intermediates is key to preventing chain‐walking isomerization events that plague related protocols. Insights gained through this study may have wider implications in selective metal‐catalyzed hydrofunctionalization reactions. 相似文献
993.
Heng Zhang Fangfang Chen Oier Lakuntza Uxue Oteo Lixin Qiao Maria Martinez‐Ibaez Haijin Zhu Javier Carrasco Maria Forsyth Michel Armand 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(35):12198-12203
Suppressing the mobility of anionic species in polymer electrolytes (PEs) is essential for mitigating the concentration gradient and internal cell polarization, and thereby improving the stability and cycle life of rechargeable alkali metal batteries. Now, an ether‐functionalized anion (EFA) is used as a counter‐charge in a lithium salt. As the salt component in PEs, it achieves low anionic diffusivity but sufficient Li‐ion conductivity. The ethylene oxide unit in EFA endows nanosized self‐agglomeration of anions and trapping interactions between the anions and its structurally homologous matrix, poly(ethylene oxide), thus suppressing the mobility of negative charges. In contrast to previous strategies of using anion traps or tethering anions to a polymer/inorganic backbone, this work offers a facile and elegant methodology on accessing selective and efficient Li‐ion transport in PEs and related electrolyte materials (for example, composites and hybrid electrolytes). 相似文献
994.
995.
Jae Hyun Kim Illan Kim Yeonghun Song Min Jung Kim Sanghee Kim 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(32):11134-11138
The total synthesis of (+)‐neooxazolomycin was achieved from the amino‐acid d ‐serine. The efficiency of this approach is derived from the use of principles of memory of chirality and dynamic kinetic resolution in the intramolecular aldol reaction of a serine derivative to build the densely functionalized lactam framework and to install three contiguous stereocenters. The key intermediate was readily elaborated to the target natural product. 相似文献
996.
Yan Jin Si Li Zhen Han Bing‐Jie Yan Hai‐Yang Li Xi‐Yan Dong Shuang‐Quan Zang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(35):12271-12276
Chiral assembly and asymmetric synthesis are critically important for the generation of chiral metal clusters with chiroptical activities. Here, a racemic mixture of [K(CH3OH)2(18‐crown‐6)]+[Cu5(StBu)6]? ( 1?CH3OH ) in the chiral space group was prepared, in which the chiral red‐emissive anionic [Cu5(StBu)6]? cluster was arranged along a twofold screw axis. Interestingly, the release of the coordinated CH3OH of the cationic units turned the chiral 1?CH3OH crystal into a mesomeric crystal [K(18‐crown‐6)]+[Cu5(StBu)6]? ( 1 ), which has a centrosymmetric space group, by adding symmetry elements of glide and mirror planes through both disordered [Cu5(StBu)6]? units. The switchable chiral/achiral rearrangement of [Cu5(StBu)6]? clusters along with the capture/release of CH3OH were concomitant with an intense increase/decrease in luminescence. We also used cationic chiral amino alcohols to induce the chiral assembly of a pair of enantiomers, [d /l ‐valinol(18‐crown‐6)]+[Cu5(StBu)6]? ( d /l ‐Cu5V ), which display impressive circularly polarized luminescence (CPL) in contrast to the CPL‐silent racemic mixture of 1?CH3OH and mesomeric 1 . 相似文献
997.
Fei Ye Florian Berger Hao Jia Joseph Ford Alan Wortman Jonas Brgel Christophe Genicot Tobias Ritter 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(41):14757-14761
Incorporation of the CF3 group into arenes has found increasing importance in drug discovery. Herein, we report the first photoredox‐catalyzed cross‐coupling of aryl thianthrenium salts with a copper‐based trifluoromethyl reagent, which enables a site‐selective late‐stage trifluoromethylation of arenes. The reaction proceeds with broad functional group tolerance, even for complex small molecules on gram scale. The method was further extended to produce pentafluoroethylated derivatives. 相似文献
998.
Yao Zhang Bo Han Shaolin Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(39):13998-14002
The direct and selective functionalization of relatively simple and readily accessible precursors to produce highly functionalized alkyl boronates is a synthetically useful process. Herein we report a NiH‐catalyzed remote hydroarylation process that can, through a synergistic combination of chain walking and subsequent cross‐coupling, introduce an aryl group at the adjacent carbon atom of alkyl boronates under mild conditions. By means of a preliminary experiment with moderate enantioselectivity, it was shown that an asymmetric version could also be realized. 相似文献
999.
Roly J. Armstrong Wasim M. Akhtar Tom A. Young Fernanda Duarte Timothy J. Donohoe 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(36):12688-12692
Hydrogen borrowing catalysis serves as a powerful alternative to enolate alkylation, enabling the direct coupling of ketones with unactivated alcohols. However, to date, methods that enable control over the absolute stereochemical outcome of such a process have remained elusive. Here we report a catalytic asymmetric method for the synthesis of enantioenriched cyclohexanes from 1,5‐diols via hydrogen borrowing catalysis. This reaction is mediated by the addition of a chiral iridium(I) complex, which is able to impart high levels of enantioselectivity upon the process. A series of enantioenriched cyclohexanes have been prepared and the mode of enantioinduction has been probed by a combination of experimental and DFT studies. 相似文献
1000.
Feng Su Guangmei Chen Peter A. Korevaar Fangfang Pan Huijiao Liu Zongxia Guo Albertus P. H. J. Schenning Hui‐Jun Zhang Jianbin Lin Yun‐Bao Jiang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(43):15417-15421
The formation of well‐defined finite‐sized aggregates represents an attractive goal in supramolecular chemistry. In particular, construction of discrete π‐stacked dye assemblies remains a challenge. Reported here is the design and synthesis of a novel type of discrete π‐stacked aggregate from two comparable perylenediimide (PDI) dyads ( PEP and PBP ). The criss‐cross PEP ‐ PBP dimers in solution and ( PBP ‐ PEP )‐( PEP ‐ PBP ) tetramers in the solid state are well elucidated using single‐crystal X‐ray diffraction, dynamic light scattering, and diffusion‐ordered NMR spectroscopy. Extensive π–π stacking between the PDI units of PEP and PBP as well as repulsive interactions of swallow‐tailed alkyl substituents are responsible for the selective formation of discrete dimer and tetramer stacks. Our results reveal a new approach to preparing discrete π stacks that are appealing for making assemblies with well‐defined optoelectronic properties. 相似文献