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91.
92.
Daisuke Sawada Yoshiharu Nishiyama Loukas Petridis R. Parthasarathi S. Gnanakaran V. Trevor Forsyth Masahisa Wada Paul Langan 《Cellulose (London, England)》2013,20(4):1563-1571
The neutron structure of a complex of EDA with cellulose has been determined to reveal the location of hydrogen atoms involved in hydrogen-bonding. EDA disrupts the hydrogen-bonding pattern of naturally occurring cellulose by accepting a strong hydrogen-bond from the O6 hydroxymethyl group as the conformation of this group is rotated from tg to gt. The O3-H·O5 intrachain hydrogen-bond commonly found in cellulose allomorphs is observed to be disordered in the neutron structure, and quantum chemistry and molecular dynamics calculations show that O3 prefers to donate to EDA. The hydrogen-bonding arrangement is highly dynamic with bonds continually being formed and broken thus explaining the difficulty in locating all of the hydrogen atoms in the neutron scattering density maps. Comparison with other polysaccharide-amino complexes supports a common underlying mechanism for amine disruption of cellulose. 相似文献
93.
Marklund GT Sadeghi S Karlsson T Lindqvist PA Nilsson H Forsyth C Fazakerley A Lucek EA Pickett J 《Physical review letters》2011,106(5):055002
Aurora, commonly seen in the polar sky, is a ubiquitous phenomenon occurring on Earth and other solar system planets. The colorful emissions are caused by electron beams hitting the upper atmosphere, after being accelerated by quasistatic electric fields at 1-2 R(E) altitudes, or by wave electric fields. Although aurora was studied by many past satellite missions, Cluster is the first to explore the auroral acceleration region with multiprobes. Here, Cluster data are used to determine the acceleration potential above the aurora and to address its stability in space and time. The derived potential comprises two upper, broad U-shaped potentials and a narrower S-shaped potential below, and is stable on a 5 min time scale. The scale size of the electric field relative to that of the current is shown to depend strongly on altitude within the acceleration region. To reveal these features was possible only by combining data from the two satellites. 相似文献
94.
Insight into Local Structure and Molecular Dynamics in Organic Solid‐State Ionic Conductors 下载免费PDF全文
Dr. Haijin Zhu Dr. Fangfang Chen Liyu Jin Dr. Luke A. O'Dell Prof. Dr. Maria Forsyth 《Chemphyschem》2014,15(17):3720-3724
Elucidating the rate and geometry of molecular dynamics is particularly important for unravelling ion‐conduction mechanisms in electrochemical materials. The local molecular motions in the plastic crystal 1‐ethyl‐1‐methylpyrrolidinium tetrafluoroborate ([C2mpyr][BF4]) are studied by a combination of quantum chemical calculations and advanced solid‐state nuclear magnetic resonance spectroscopy. For the first time, a restricted puckering motion with a small fluctuation angle of 25° in the pyrrolidinium ring has been observed, even in the low‐temperature phase (?45 °C). This local molecular motion is deemed to be particularly important for the material to maintain its plasticity, and hence, its ion mobility at low temperatures. 相似文献
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Dr. Heng Zhang Dr. Chunmei Li Dr. Gebrekidan Gebresilassie Eshetu Prof. Stéphane Laruelle Prof. Sylvie Grugeon Prof. Karim Zaghib Prof. Christian Julien Prof. Alain Mauger Prof. Dominique Guyomard Prof. Teófilo Rojo Dr. Nuria Gisbert-Trejo Prof. Stefano Passerini Prof. Xuejie Huang Prof. Zhibin Zhou Prof. Patrik Johansson Prof. Maria Forsyth 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(2):542-546
Lithium-ion batteries (LIBs) have become ubiquitous power sources for small electronic devices, electric vehicles, and stationary energy storage systems. Despite the success of LIBs which is acknowledged by their increasing commodity market, the historical evolution of the chemistry behind the LIB technologies is laden with obstacles and yet to be unambiguously documented. This Viewpoint outlines chronologically the most essential findings related to today's LIBs, including commercial electrode and electrolyte materials, but furthermore also depicts how the today popular and widely emerging solid-state batteries were instrumental at very early stages in the development of LIBs. 相似文献
98.
The TDDFT method is first applied in a series of tetra-nuclear transition metal clusters studies for nonlinear optical properties. The results indicate that the charge transfer inside the metal core [MCu3X4] (M=W, Mo; X=S, O, Cl, Se, Br) makes contribution to the optical nonlinearity. It is possible to enhance the hyperpolarizability by substituting the ligands of the clusters. 相似文献
99.
Deacon GB Forsyth CM Behrsing T Konstas K Forsyth M 《Chemical communications (Cambridge, England)》2002,(23):2820-2821
The syntheses and structures of the novel Ce-Fe bimetallic complexes [[Fe(sal)2(bpy)]2Ce(NO3)(H2O)3].EtOH and [[Fe(sal)2(bpy)]4Ce2(H2O)11][salH]2.EtOH.3H2O (salH2 = salicylic acid) suggest Fe(3+)-sal2- units and Ce-OC(R)O-Fe bridging contribute to the formation of corrosion inhibitive layers on steel surfaces exposed to [Ce(salH)3(H2O)]. 相似文献
100.
Prof. Dr. Marcus L. Cole Prof. Dr. Glen B. Deacon Dr. Craig M. Forsyth Prof. Dr. Peter C. Junk Dr. Kristina Konstas Dr. Jun Wang Henry Bittig Daniel Werner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(4):1410-1420
New reactive, divalent lanthanoid formamidinates [Yb(Form)2(thf)2] (Form=[RNCHNR]; R=o‐MeC6H4 (o‐TolForm; 1 ), 2,6‐Me2C6H3 (XylForm; 2 ), 2,4,6‐Me3C6H2 (MesForm; 3 ), 2,6‐Et2C6H3 (EtForm; 4 ), o‐PhC6H4 (o‐PhPhForm; 5 ), 2,6‐iPr2C6H3 (DippForm; 6 ), o‐HC6F4 (TFForm; 7 )) and [Eu(DippForm)2(thf)2] ( 8 ) have been prepared by redox transmetallation/protolysis reactions between an excess of a lanthanoid metal, Hg(C6F5)2 and the corresponding formamidine (HForm). X‐ray crystal structures of 2 – 6 and 8 show them to be monomeric with six‐coordinate lanthanoid atoms, chelating N,N′‐Form ligands and cis‐thf donors. However, [Yb(TFForm)2(thf)2] ( 7 ) crystallizes from THF as [Yb(TFForm)2(thf)3] ( 7 a ), in which ytterbium is seven coordinate and the thf ligands are “pseudo‐meridional”. Representative complexes undergo C? X (X=F, Cl, Br) activation reactions with perfluorodecalin, hexachloroethane or 1,2‐dichloroethane, and 1‐bromo‐2,3,4,5‐tetrafluorobenzene, giving [Yb(EtForm)2F]2 ( 9) , [Yb(o‐PhPhForm)2F]2 ( 10) , [Yb(o‐PhPhForm)2Cl(thf)2] ( 11) , [Yb(DippForm)2Cl(thf)] ( 12) and [Yb(DippForm)2Br(thf)] ( 16) . X‐ray crystallography has shown 9 to be a six‐coordinate, fluoride‐bridged dimer, 12 and 16 to be six‐coordinate monomers with the halide and thf ligands cis to each other, and 11 to have a seven‐coordinate Yb atom with “pseudo‐meridional” unidentate ligands and thf donors cis to each other. The analogous terbium compound [Tb(DippForm)2Cl(thf)2] ( 13 ), prepared by metathesis, has a similar structure to 11 . C? Br activation also accompanies the redox transmetallation/protolysis reactions between La, Nd or Yb metals, Hg(2‐BrC6F4)2, and HDippForm, yielding [Ln(DippForm)2Br(thf)] complexes (Ln=La ( 14 ), Nd ( 15 ), Yb ( 16 )). 相似文献