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921.
《应用有机金属化学》2017,31(9)
A β‐diketimine ligand with vinylidene substitution at γ‐carbon, CH2C(CH3CNAr)2 (Ar = 2,6‐diisopropylphenyl) ( L 2 ), was synthesized by treating β‐diketimine H2C(CH3CNAr)2 with n ‐BuLi followed by paraformaldehyde. L 2 formed the homobimetallic ether‐bridged β‐diketiminate complex [O{(CH2‐β‐diketiminate)Pd(OAc)}2] ( 1 ) with (PdOAc)2. It also gave complexes [L2PdCl2] ( 2 ) and [L2NiBr2] ( 3 ) when treated with PdCl2(CH3CN)2 and NiBr2(dimethoxyethane), respectively. All the compounds were characterized using 1H/13C NMR spectroscopy and single‐crystal X‐ray diffraction studies. The catalytic activity of Pd and Ni complexes 1 , 2 and 3 was explored in Heck coupling and alkyne trimerization reactions and it was found that they are very good catalysts. The results are reported in detail. 相似文献
922.
《应用有机金属化学》2017,31(9)
Because of the side effects and drug resistance of cisplatin, a basic clinically approved chemotherapeutic drug, a new attempt is reported to develop a novel antitumor drug based on complexation of iron metal ion with organic moiety that may be effective and safer. A newly synthesized iron(III) diacetylmonoxime‐2‐hydrazinopyridine complex was tested firstly for its cytotoxicity and superoxide dismutase (SOD)‐mimic activity in vitro then for its antitumor activity against Ehrlich ascites carcinoma (EAC) and the related biochemical alterations in vivo in comparison with cisplatin. The complex showed 80.88% SOD‐mimic activity and IC50 of 2.6 μg ml−1. In EAC‐bearing mice, in a dose‐dependent manner, Fe(III) complex treatment exhibited significant hematological profile improvements, tumor volume, viable cell count and hepatic lipid peroxidation level decreases, life span extension, hepatic glutathione and total antioxidant capacity levels enhancements, hepatic SOD and catalase activities augmentations, liver function tests alterations attenuations, and hepatocyte nucleic acids content normalization. Thus, the Fe(III) diacetylmonoxime‐2‐hydrazinopyridine complex is a novel, promising, less toxic antitumor agent. Its killing of tumor cells may be via a reactive oxygen species scavenging mechanism. 相似文献
923.
《Analytical letters》2012,45(17):1497-1512
Abstract Hexamethylphosphoramide (HMPA) gives, in aqueous solutions in the presence of SCN? ions, complexes with many metal ions, which absorb in the visible region of spectrum. The spectra have been studied in function of ligand concentration and pH for Co, Ni and Fe complexes. For the Co complex an equation was found that describes the behaviour of the absorption vs. SCN? and HMPA concentration. Absorption follows Lambert-Beer law and can be used for analytical determinations. Analysis of solutions containing Ni and Co in various ratios of concentration has been performed and results are discussed. Co, Ni and Fe content of an alloy has been measured by this way. 相似文献
924.
C. Jandl S. Stegbauer A. Pthig 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(7):509-513
In the coordination chemistry of palladium, dimers bridged via halides are a common motif. Higher oligomers, however, are still rare. We report the structure of an alternating eight‐membered [Pd4Br4]4− ring framed by cycloheptatrienide ligands, which was obtained by cocrystallization of dimers and tetramers of the complex salt bromido{η3‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II) tetrafluoroborate, namely bis[di‐μ‐bromido‐bis({η3‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II))] cyclo‐tetra‐μ‐bromido‐tetrakis({η3‐[3‐(2,6‐diisopropylphenyl)imidazolium‐1‐yl]cycloheptatrienido}palladium(II)) octakis(tetrafluoroborate) dichloromethane octasolvate, [Pd4Br4(C22H26N2)4][Pd2Br2(C22H26N2)2]2(BF4)8·8CH2Cl2. These dimers and tetramers form a highly dynamic equilibrium in solution which was studied by low‐temperature NMR spectroscopy. In the light of the presented results, tetrameric PdII species can be assumed to co‐exist as a second species in many cases where by current knowledge only a dimeric compound would be expected. 相似文献
925.
Chunhui Dai Yuxiang Wang Yiwu Quan Qingmin Chen Yixiang Cheng Chengjian Zhu 《Journal of polymer science. Part A, Polymer chemistry》2014,52(21):3080-3086
The β‐diketonate‐based achiral polymer P‐1 could be synthesized by the polymerization of 3,7‐dibromo‐2,8‐dimethoxy‐5,5‐dioctyl‐5H‐dibenzo[b,d]silole ( M1 ) with (Z)?1,3‐bis(4‐ethynylphenyl)?3‐hydroxyprop‐en‐1‐one ( M2 ) via typical Sonogashira coupling reaction. The β‐diketonate unit in the main chain backbone of P‐1 can further coordinate with Eu(TTA)x [TTA? = 4,4,4‐trifluoro‐1‐(thiophen‐2‐yl)butane‐1,3‐dionate anion, X = 1, 2, 3] to afford corresponding Eu(III)‐containing polymer complexes. The resulting achiral polymer complex P‐2 (X = 2) can exhibit strong circular dichroism (CD) response toward both N‐Boc‐l and d‐ proline enantiomers. The CD signal was preliminarily attributed to coordination induction between chiral N‐Boc‐proline and the Eu(III) complex moiety. The linear regression analysis of CD sensing shows a good agreement between the magnitude of molar ellipticity and concentration of chiral N‐Boc‐l or d‐ proline, which indicates this kind Eu(III)‐containing achiral polymer complex can be used as a chiral probe for enantioselective recognition of N‐Boc‐l or d‐ proline enantiomers based on Cotton effect of CD spectra. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3080–3086 相似文献
926.
Siegfried Cools Bram Reps Wim Vanroose 《Numerical Linear Algebra with Applications》2014,21(4):513-533
In this paper, we construct and analyze a level‐dependent coarse grid correction scheme for indefinite Helmholtz problems. This adapted multigrid (MG) method is capable of solving the Helmholtz equation on the finest grid using a series of MG cycles with a grid‐dependent complex shift, leading to a stable correction scheme on all levels. It is rigorously shown that the adaptation of the complex shift throughout the MG cycle maintains the functionality of the two‐grid correction scheme, as no smooth modes are amplified in or added to the error. In addition, a sufficiently smoothing relaxation scheme should be applied to ensure damping of the oscillatory error components. Numerical experiments on various benchmark problems show the method to be competitive with or even outperform the current state‐of‐the‐art MG‐preconditioned Krylov methods, for example, complex shifted Laplacian preconditioned flexible GMRES. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
927.
A series of aluminum dimethyl complexes 1 – 6 bearing N‐[2‐(pyrrolidinyl)benzyl]anilido ligands were synthesized and well characterized. The molecular structure of complex 1 determined by an X‐ray diffraction study indicates the bidentate chelating mode of the pyrrolidinyl‐anilido ligand. In the absence of a coinitiator, these complexes exhibited excellent control toward the polymerizations of ε‐caprolactone and rac‐lactide, affording polyesters with quite narrow molecular weight distributions (Mw/Mn = 1.04–1.26). The end group analysis of ε?CL oligomer via 1H NMR and ESI‐TOF MS methods gave strong support to the hypothesis that the polymerization catalyzed by these aluminum complexes proceeds via a coordination‐insertion mechanism involving a unique Al? N (amido) bond initiation. Via 1H NMR scale oligomerization studies, it is suggested that the insertion of the first lactide monomer into Al? N bond of the complex is much easier than the insertion of lactide monomer into the newly formed Al? O (lactate) bond and might also be easier than the insertion of the first ε?CL monomer into Al? N bond. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3096–3106 相似文献
928.
Zhiyong SunGangquan Si 《Communications in Nonlinear Science & Numerical Simulation》2012,17(8):3461-3463
In this comment letter we point out that the main result of the recent paper [Xu Y, Zhou W, Fang J, Sun W. Topology identification and adaptive synchronization of uncertain complex networks with adaptive double scaling functions. Commun Nonlinear Sci Numer Simul 2011;16(18):3337-43] has certain errors. The mistakes are corrected and a correct version is presented in this letter. We further indicate that a sufficient condition has been neglected in a series of articles discussing the same topic of network topology identification; hence we hope this letter can help clarify some unclear concepts about this topic. 相似文献
929.
The electronic absorption spectra of crystals of the title componds were recorded and the experimental results were explained quantitatively with the ligand field theory and the radial wave function of bound Cu(II) cation. With these spactra, the range of magnetic interactions between two Cu(II) ions of the title compounds are discussed. 相似文献
930.
Synthesis,spectral, DFT calculations and antibacterial studies of Fe(III) complexes of new fluorescent Schiff bases derived from imidazo[4',5':3,4]benzo[1,2‐c]isoxazole
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New fluorescent heterocyclic ligands were synthesized by the reaction of 8‐(4‐chlorophenyl)‐3‐alkyl‐3H‐imidazo[4',5':3,4]benzo [1,2‐c]isoxazol‐5‐amine with p‐hydroxybenzaldehyde and p‐chlorobenzaldehyde in good yields. The coordination ability of the ligands with Fe3+ ion was examined in an aqueous metanolic solution. Schiff base ligands and their metal complexes were characterized by elemental analyses, IR, UV–vis, mass, and NMR spectra. The optical properties of the compounds were investigated and the results showed that the fluorescence of all compounds is intense and their obtained emission quantum yields are around 0.15 – 0.53. Optimized geometries and assignment of the IR bands and NMR chemical shifts of the new complexes were also computed by using density functional theory (DFT) methods. The DFT‐calculated vibrational wavenumbers and NMR chemical shifts are in good agreement with the experimental values, confirming suitability of the optimized geometries for Fe(III) complexes. Also, the 3D‐distribution map for HOMO and LUMO of the compounds were obtained. The new compounds showed potent antibacterial activity and their antibacterial activity (MIC) against Gram‐positive and Gram‐negative bacterial species were also determined. Results of antibacterial test revealed that coordination of ligands to Fe(III) leads to improvement in the antibacterial activity. 相似文献