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101.
102.
Theroleofthiolestersasacylatingagentsinbiochemicalprocessesandtheirhighreactivitywithvariousnucleophiles,hasmadethemanattractivesyntheticintermediateinorganicsynthesis'-'.Manynewmethodshavebeendevelopedforthepreparationofthiolestersinrecentyears'-",forexample,thereactionbetweensodiumthiobenzoateandarenediazoniumtetrafluoroborates',tTedrientofnitrosoamidesornitroamideswithmercaptansinthepresenceofsodiumhydride',thecobaltcarbonylcatalyzedcarbonylationofmercaptans'andthecobaltchloridecatalyzedcou… 相似文献
103.
Jianming Guo Er‐xin Shang Jin‐ao Duan Yuping Tang Dawei Qian Shulan Su 《Rapid communications in mass spectrometry : RCM》2010,24(4):443-453
In drug metabolism research, the setting up of a complex series of mass spectrometry experiments and the subsequent analysis of the large amounts of data produced are often time‐consuming. In this paper, we describe a strategy using ultra‐performance liquid chromatography/quadrupole time‐of‐flight mass spectrometry (UPLC/QTOFMS) with automated data analysis software (MetaboLynx?) for fast analysis of the metabolic profile of flavonoids in Abelmoschus manihot. Rat plasma and urine samples collected 1 h and 0–12 h after oral administration of Abelmoschus manihot were analyzed by UPLC/QTOFMS within 15 min. The post‐acquisition data were processed using MetaboLynx. With key parameters carefully set, MetaboLynx is able to show the presence of a wide range of metabolites with only a limited requirement for manual intervention and data interpretation time. A total of 16 and 38 metabolites were identified in plasma and urine compared with blank samples. The results indicated that methylation and glucuronidation after deglycosylation were the major metabolic pathways of flavonoid glycosides in Abelmoschus manihot. The present study provided important information about the metabolism of flavonoid glycosides in Abelmoschus manihot which will be helpful for fully understanding the mechanism of action of this herb. Furthermore, this work demonstrated the potential of the UPLC/QTOFMS approach using MetaboLynx for fast and automated identification of metabolites from Chinese herbal medicines. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
104.
Yelda Bingöl Alpaslan Nevin Süleymanoğlu Emin Öztekin Ferda Erşahin Erbil Ağar Şamil Işık 《Journal of chemical crystallography》2010,40(11):950-956
Abstract
The molecular and crystal structure of the title compound, C14H11Cl2NO, has been determined by X-ray single crystal diffraction technique. The compound crystallizes in the orthorhombic, space group Pbca with unit cell dimensions a = 7.5537(10) ?, b = 11.5518(13) ?, c = 29.760(4) ?, M r = 280.14, V = 2596.8(6) ?3, Z = 8, R 1 = 0.065 and wR 2 = 0.191. The title compound exists in the enol–imine tautomeric form with a strong intramolecular O–H···N hydrogen bond. The dihedral angle between the two benzene rings is 37.66(15)°. The asymmetric unit in the crystal structure contains only one neutral molecule. Calculational studies were performed by using AM1, PM3, PM6 semi-empirical and DFT methods. Geometry optimizations of compound have been carried out by using three semi-empirical methods and DFT method and bond lengths, bond and torsion angles of title compound have been determined. Dipole moments (Debye) and the energy parameters of compound (kcal/mol) were calculated by using above mentioned calculation methods. Atomic charge distribution has been obtained from AM1, PM3, PM6 and DFT. In order to determine conformational flexibility on the molecule, molecular energy profile of the title compound was obtained with respect to the selected torsion angle T(N1–C7–C1–C2), which is varied from −180° to +180° in every 10 via PM3 semi-empirical method. 相似文献105.
Andrew G. Tennyson Dr. Robert J. Ono Todd W. Hudnall Dr. Dimitri M. Khramov Dr. Joyce A. V. Er Justin W. Kamplain Dr. Vincent M. Lynch Dr. Jonathan L. Sessler Prof. Christopher W. Bielawski Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(1):304-315
Reaction of bromanil with N,N′‐dimesitylformamidine followed by deprotonation with NaN(SiMe3)2 afforded 1,1′,3,3′‐tetramesitylquinobis(imidazolylidene) ( 1 ), a bis(N‐heterocyclic carbene) (NHC) with two NHC moieties connected by a redox active p‐quinone residue, in 72 % yield of isolated compound. Bimetallic complexes of 1 were prepared by coupling to FcN3 ( 2 ) or FcNCS ( 3 ; Fc=ferrocenyl) or coordination to [M(cod)Cl] ( 4 a or 4 b , where M=Rh or Ir, respectively; cod=1,5‐cyclooctadiene). Treatment of 4 a and 4 b with excess CO(g) afforded the corresponding [M(CO)2Cl] complexes 5 a and 5 b , respectively. Analysis of 2 – 5 by NMR spectroscopy and X‐ray diffraction indicated that the electron‐deficient quinone did not significantly affect the inherent spectral properties or coordination chemistry of the flanking imidazolylidene units, as compared to analogous NHCs. Infrared spectroscopy and cyclic voltammetry revealed that decreasing the electron density at MLn afforded an increase in the stretching energy and a decrease in the reduction potential of the quinone, indicative of metal–quinone electronic interaction. Differential pulse voltammetry and chronoamperometry of the metal‐centered oxidations in 2 – 4 revealed two single, one‐electron peaks. Thus, the metal atoms bound to 1 are oxidized at indistinguishable potentials and do not appear electronically coupled. However, the metal–quinone interaction was used to increase the electron density at coordinated metal atoms. Infrared spectroelectrochemistry revealed that the average νCO values for 5 a and 5 b decreased by 14 and 15 cm?1, respectively, upon reduction of the quinone embedded within 1 . These shifts correspond to 10 and 12 cm?1 decreases in the Tolman electronic parameter of this ditopic ligand. 相似文献
106.
Er‐Lei Yang Yun‐Liang Jiang Yu‐Ling Wang Qing‐Yan Liu 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(9):m231-m234
The title compound, {[Cd2(C10H12N2O8)(H2O)]·H2O}n, consists of two crystallographically independent CdII cations, one ethylenediaminetetraacetate (edta) tetraanion, one coordinated water molecule and one solvent water molecule. The coordination of one of the Cd atoms, Cd1, is composed of five O atoms and two N atoms from two tetraanionic edta ligands in a distorted pentagonal–bipyramidal coordination geometry. The other Cd atom, Cd2, is six‐coordinated by five carboxylate O atoms from five edta ligands and one water molecule in a distorted octahedral geometry. Two neighbouring Cd1 atoms are bridged by a pair of carboxylate O atoms to form a centrosymmetric [Cd2(edta)2]4− unit located on the inversion centre, which is further extended into a two‐dimensional layered structure through Cd2—O bonds. There are hydrogen bonds between the coordinated water molecules and carboxylate O atoms within the layer. The solvent water molecules occupy the space between the layers and interact with the host layers through O—H...O and C—H...O interactions. 相似文献
107.
108.
Let F be a field with characteristic 0, V = Fn the n-dimensional vector space over F and let G be a finite pseudo-reflection group which acts on V . Let χ : G→ F* be a 1- dimensional representation of G. In this article we show that χ(g) = (detg)α(0 ≤ α ≤ r - 1), where g ∈ G and r is the order of g. In addition, we characterize the relation between the relative invariants and the invariants of the group G, and then we use Molien’s Theorem of invariants to compute the Poincar′e series of relative invariants. 相似文献
109.
Quasiperiodic solutions of degenerate linear systems of second-order ordinary differential equations
We establish sufficient conditions for the existence of quasiperiodic solutions of a system of ordinary second-order differential
equations with degenerate symmetric matrix of the second derivatives for an arbitrary quasiperiodic inhomogeneity. 相似文献
110.
Jeong SC Herrmann N Fan ZG Freifelder R Gobbi A Hildenbrand KD Krämer M Randrup J Reisdorf W Schüll D Sodan U Teh K Wessels JP Pelte D Trzaska M Wienold T Alard JP Amouroux V Basrak Z Bastid N Belayev IM Berger L Bini M Blaich T Boussange S Buta A Caplar R Cerruti C Cindro N Coffin JP Dona R Dupieux P Erö J Fintz P Fodor Z Fraysse L Frolov S Grigorian Y Guillaume G Hölbling S Houari A Jundt F Kecskemeti J Koncz P Korchagin Y Kotte R Kuhn C Ibnouzahir M Legrand I Lebedev A Maguire C Manko V 《Physical review letters》1994,72(22):3468-3471