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81.
82.
Dr. Gaëlle Charron Dr. Elena Malkin Dr. Guillaume Rogez Dr. Luke J. Batchelor Dr. Sandra Mazerat Dr. Régis Guillot Dr. Nathalie Guihéry Dr. Anne‐Laure Barra Dr. Talal Mallah Dr. Hélène Bolvin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(47):16850-16862
By using complementary experimental techniques and first‐principles theoretical calculations, magnetic anisotropy in a series of five hexacoordinated nickel(II) complexes possessing a symmetry close to C2v, has been investigated. Four complexes have the general formula [Ni(bpy)X2]n+ (bpy=2,2′‐bipyridine; X2=bpy ( 1 ), (NCS?)2 ( 2 ), C2O42? ( 3 ), NO3? ( 4 )). In the fifth complex, [Ni(HIM2‐py)2(NO3)]+ ( 5 ; HIM2‐py=2‐(2‐pyridyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐hydroxy), which was reported previously, the two bpy bidentate ligands were replaced by HIM2‐py. Analysis of the high‐field, high‐frequency electronic paramagnetic resonance (HF‐HFEPR) spectra and magnetization data leads to the determination of the spin Hamiltonian parameters. The D parameter, corresponding to the axial magnetic anisotropy, was negative (Ising type) for the five compounds and ranged from ?1 to ?10 cm?1. First‐principles SO‐CASPT2 calculations have been performed to estimate these parameters and rationalize the experimental values. From calculations, the easy axis of magnetization is in two different directions for complexes 2 and 3 , on one hand, and 4 and 5 , on the other hand. A new method is proposed to calculate the g tensor for systems with S=1. The spin Hamiltonian parameters (D (axial), E (rhombic), and gi) are rationalized in terms of ordering of the 3 d orbitals. According to this orbital model, it can be shown that 1) the large magnetic anisotropy of 4 and 5 arises from splitting of the eg‐like orbitals and is due to the difference in the σ‐donor strength of NO3? and bpy or HIM2‐py, whereas the difference in anisotropy between the two compounds is due to splitting of the t2g‐like orbitals; and 2) the anisotropy of complexes 1 – 3 arises from the small splitting of the t2g‐like orbitals. The direction of the anisotropy axis can be rationalized by the proposed orbital model. 相似文献
83.
Dr. Achraf Noureddine Dr. Magali Gary‐Bobo Dr. Laure Lichon Dr. Marcel Garcia Prof. Jeffrey I. Zink Dr. Michel Wong Chi Man Dr. Xavier Cattoën 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(28):9624-9630
Bis(clickable) mesoporous silica nanospheres (ca. 100 nm) were obtained by the co‐condensation of TEOS with variable amounts (2–5 % each) of two clickable organosilanes in the presence of CTAB. Such nanoparticles could be easily functionalized with two independent functions using the copper‐catalyzed alkyne‐azide cycloaddition (CuAAC) reaction to transform them into nanomachines bearing cancer cell targeting ligands with the ability to deliver drugs on‐demand. The active targeting was made possible after anchoring folic acid by CuAAC click reaction, whereas the controlled delivery was performed by clicked azobenzene fragments. Indeed, the azobenzene groups are able to obstruct the pores of the nanoparticles in the dark whereas upon irradiation in the UV or in the blue range, their trans‐to‐cis photoisomerization provokes disorder in the pores, enabling the delivery of the cargo molecules. The on‐command delivery was proven in solution by dye release experiments, and in vitro by doxorubicin delivery. The added value of the folic acid ligand was clearly evidenced by the difference of cell killing induced by doxorubicin‐loaded nanoparticles under blue irradiation, depending on whether the particles featured the clicked folic acid ligand or not. 相似文献
84.
Synthesis and Thermophysical Properties of Ether‐Functionalized Sulfonium Ionic Liquids as Potential Electrolytes for Electrochemical Applications 下载免费PDF全文
Dr. Erwan Coadou Dr. Peter Goodrich Alex R. Neale Dr. Laure Timperman Prof. Christopher Hardacre Dr. Johan Jacquemin Prof. Mérièm Anouti 《Chemphyschem》2016,17(23):3992-4002
During this work, a novel series of hydrophobic room temperature ionic liquids (ILs) based on five ether functionalized sulfonium cations bearing the bis{(trifluoromethyl)sulfonyl}imide, [NTf2]? anion were synthesized and characterized. Their physicochemical properties, such as density, viscosity and ionic conductivity, electrochemical window, along with thermal properties including phase transition behavior and decomposition temperature, have been measured. All of these ILs showed large liquid range temperature, low viscosity, and good conductivity. Additionally, by combining DFT calculations along with electrochemical characterization it appears that these novel ILs show good electrochemical stability windows, suitable for the potential application as electrolyte materials in electrochemical energy storage devices. 相似文献
85.
Christian Amatore Anny Jutand Laure Mensah 《Journal of organometallic chemistry》2007,692(7):1457-1464
Specific chiral ligands have been designed by Trost et al. to perform enantioselective Pd-catalyzed allylic alkylations. It is shown that the Pd(0) complex formed by addition of the Trost ligand (4) to Pd0(dba)2 is not stable in most solvents (acetone, DMF, CH2Cl2). Indeed, Pd0(dba)(4) leads to the formation of a stable PdII complex 5 (X-ray structure), likely by activation of the two N-H bonds of the ligand by the Pd0 centre. The formation of the PdII complex competes with the reaction of Pd0(4) with (E)-PhCHCH-CH(OAc)-Ph, excluding any investigation of the kinetics of the latter reaction. The ionization steps from intermediate (η2-PhCHCH-CH(OAc)-Ph)Pd0(4) were found to be very slow. The cationic P,P complex [(η3-Ph-CH-CH-CH-Ph)Pd(4)]+, expected to be generated by addition of 2 equiv. of 4 to the precursor [(η3-Ph-CH-CH-CH-Ph)Pd(μ-Cl)]2, in the presence of a chloride scavenger, leads to a complex mixture whereas addition of 1 equiv. of 4 affords a stable bis-cationic PdII complex {[(η3-Ph-CH-CH-CH-Ph)Pd]2(4)]}2+, (X-ray structure) via a P,O complexation of each allyl-Pd moieties. This dissymmetric P,O coordination will favour the enantioselectivity of Pd-catalyzed allylic alkylation of (E)-PhCHCH-CH(OAc)-Ph by the control of the regioselectivity of the nucleophilic attack onto the allylic ligand which is responsible of the enantioselectivity of the overall catalytic reaction. 相似文献
86.
87.
88.
This letter describes an efficient and enantioselective conjugate addition of highly stable potassium trifluoro(organo)borates to α,β-unsaturated esters. This reaction, catalyzed by chiral rhodium(I) complexes, affords Michael adducts with high yields and enantiomeric excesses up to 96%. 相似文献
89.
9-Membered rings are readily constructed through a radical addition-cyclisation sequence on a 1,6-dien-3-ol system followed by a Grob-type fragmentation. 相似文献
90.
Marie‐Laure Louillat‐Habermeyer Rongwei Jin Prof. Dr. Frederic W. Patureau 《Angewandte Chemie (International ed. in English)》2015,54(13):4102-4104
A method was developed for the direct dehydrogenative construction of C? N bonds between unprotected phenols and a series of cyclic anilines without resorting to any kind of metal activation of either substrate and without the use of halides. The resulting process relies on the exclusively organic activation of molecular oxygen and the subsequent oxidation of the aniline substrate. This allows the coupling of ubiquitous phenols, thus furnishing aminophenols through an atom‐economical and most sustainable dehydrogenative amination method. This new reactivity, which relies on the intrinsic organic reactivity of cumene in what can be seen as a modified Hock activation process of oxygen, is expected to have a large impact on the formation of C? N bonds in organic synthesis. 相似文献