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991.
Aihara H Alston-Garnjost M Avery RE Barbaro-Galtieri A Barker AR Barnes AV Barnett BA Bauer DA Bengtsson H Bintinger DL Blumenfeld BJ Bobbink GJ Bross AD Buchanan CD Buijs A Cain MP Caldwell DO Chamberlain O Chien C Clark AR Cowan GD Crane DA Dahl OI Derby KA Eastman JJ Eberhard PH Eisner AM Enomoto R Erné FC Fujii T Gabioud B Gary JW Gorn W Hauptman JM Hofmann W Huth JE Hylen J Joshi UP Kamae T Kaye HS Kees KH Kenney RW Kerth LT Ko W Koda RI Kofler RR Kwong KK Lander RL Langeveld WG Layter JG 《Physical review letters》1986,57(4):404-407
992.
Abstract— The aim of this work was to compare the translatability of poly-A-RNA from light- and dark-grown Arena seedlings, the product of which should be phytochrome. Polysomal poly-A-RNA was isolated from 4-day-old dark-grown Avena seedlings (Avena sativa L. cv. Garry) and translated in a rabbit reticulocyte lysate system. Immunoprecipitation by anti-phytochrome serum was used for measurements of specific phytochrome translation. Characterization of the translated and immunoprectpitated protein was performed by comparison with [35S]-methionine in vivo-labelled phytochrome. The specificity of the precipitation was shown by parallel use of non-specific serum and by competitive inhibition of precipitation by exogenous unlabelled phytochrome isolated by affinity chromatography. 相似文献
993.
Andreas Markwitz Horst Baumann Rolf W. Michelmann Jörg D. Meyer Eberhard F. Krimmel Klaus Bethge 《Mikrochimica acta》1997,125(1-4):337-341
Thin silicon nitride (SiN
x
) layers with the stoichiometric N/Si ratio of 1.33 in the maximum of the concentration depth distributions of nitrogen were produced by implanting 10 keV15N
2
+
in 100 silicon at room temperature under high vacuum conditions. The depth distribution of the implanted isotope was measured by resonance nuclear reaction analysis (NRA), whereas the layer structure of the implanted region and the geometrical thickness of the layers were characterised by high resolution transmission electron microscopy (TEM). SiN
x
layers with a thickness of about 30 nm were determined by NRA. Channeling Rutherford backscattering spectrometry was used to determine the disorder in the silicon substrate. Sharp interfaces of a few nanometers between the highly disordered implanted region and the crystalline structure of the substrate thickness were observed by TEM. The high thermal stability of SiN
x
layers with N/Si ratios from under to over stoichiometric could be shown by electron beam rapid thermal annealing (1100 °C for 15 s, ramping up and down 5 °C/s) and NRA. 相似文献
994.
Anderas Knnecke Peter Lepom Ronald Drre Eberhard Lippmann 《Journal of mass spectrometry : JMS》1979,14(4):227-230
The electron impact mass spectra of 5-aryl(hetaryl)-9-methyl-s-triazolo[4,3-c]tetrazolo[1,5- a]pyrimidines have been investigated. There is a general fragmentation mechanism, which forms stable cyclazinium ions by cyclization. In the case of the 5-hetaryl derivatives the proposed structures were confirmed by means of a comparison of mass analysed ion kinetic energy spectra with suitable model compounds. 相似文献
995.
[3-(1,3-Dioxo-1,3-dihydroisoindol-2-yl)-propyl]dimethyl-{6-[(1-{2-[(6-oxo-5,6-dihydro-benzo[e]pyrido[3,2-b][1,4]diazepine-11-carbonyl)amino]ethyl}piperidin-2-yl-methyl)-propylamino]hexyl}ammonium bromide a hybride containing a fragment of the antagonist of muscarinic receptor AFDX-384 and a W84 moiety known as allosteric modulator of antagonist binding, was synthesized in a divergent synthesis starting from pipecolic acid, phthalic anhydride and 3-amino-2-chloropyridine. This new microwave assisted route is very convenient and allows to modify the piperidine ring, the benzodiazepine system, the phthalimide moiety and the chains connecting the ring systems. Yields and reproducibility were satisfying. 相似文献
996.
Andreas Markwitz Horst Baumann Rolf W. Michelmann Jörg D. Meyer Eberhard F. Krimmel Klaus Bethge 《Mikrochimica acta》1997,125(1-4):313-316
15N2
+ molecular ions were implanted with 10keV (j=10 A/cm2) under high vacuum conditions close to room temperature in 100 silicon (c-Si) to study the13N depth distributions, particularly the dependence of peak concentration and dose on the ion fluence. The analysis were performed by the resonant nuclear reaction15N(p, )12C(NRA). A maximum peak concentration of 65 at.% was measured. Thin stoichiometric silicon nitride layers with a thickness of approx. 20 nm (15 at.% nitrogen at the specimen surface) were produced by this low-energy implantation of15N2
+ ions with an ion fluence of 1.5·1017 ions/cm2. NRA analysis of 38 keV15N2
+ and 19keV15N+ ion implantations were performed to compare the15N depth distributions. No significant changes in the depth distributions are measured, that means, the molecular15N2
+ ions are already disintegrated passing the very first atomic layers of the sample during implantation. Non-Rutherford RBS with4He+ ions and 3.45 MeV was performed in order to confirm the results obtained by NRA.Dedicated to Professor Dr. rer.nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday 相似文献
997.
Eberhard Steckhan 《Angewandte Chemie (International ed. in English)》1986,25(8):683-701
The electrochemical formation and regeneration of redox agents for organic syntheses (indirect electrolysis) widens the potential of electrochemistry, as higher or totally different selectivities can often be obtained while at the same time the energy input can be lowered significantly. Higher current densities can also be obtained by preventing otherwise often encountered electrode inhibition. New types of redox catalysts can be formed in-situ and can be regenerated after reaction with the substrates. This principle is of increasing importance also for the application of already known redox agents with regard to environmental protection, since large amounts of a product can be generated in a closed circuit using only relatively small amounts of the redox reagent. Consequently the operation of such a process can be greatly simplified, and the release of ecologically objectionable spent reagents into the environment can be prevented. The broad spectrum of redox catalysts currently in use includes, inter alia, metal salts in very low or high oxidation states, halogens in various oxidation states, and, in particular, a wide variety of transition-metal complexes. A great deal of progress has recently been made in the application of organic electron transfer agents, since compounds have been found that are sufficiently stable in both the reduced as well as the oxidized state. 相似文献
998.
Summary The dinuclear metallocene, ferrocenylruthenocene, is synthesized by Ullmann coupling of iodoruthenocene with a large excess of iodoferrocene in the melt phase. The compound's ligand-vibrational modes, as reflected in the i.r. spectrum, are virtually identical with those in biferrocene; so is the symmetric ring-metal-ring stretching mode manifested in the low-frequency Raman region. The mass-spectral fragmentation pattern indicates preferential loss of a cyclopentadienyl radical from the ferrocene rather than the ruthenocene unit in conformance with both the lower metal-ring bond strength in, and lower ionization energy of, the iron complex. The1H n.m.r. patterns of the two metallocene groups, at 90 MHz, are sufficiently well separated from each other to allow their individual evaluation; this finding could have a significant bearing on the characterization of ferrocenylene-ruthenocenylene copolymers of future synthetic programs. 相似文献
999.
Berry JF Bill E Bothe E Weyhermüller T Wieghardt K 《Journal of the American Chemical Society》2005,127(33):11550-11551
The ligand 1,4,8-tri-N-methyl-1,4,8,11-tetraazacyclotetradecane-11-acetic acid (Me3cyclam-acetic acid) has been synthesized by Eschweiler-Clarke methylation of cyclam-acetic acid, and the iron(III) complex [(Me3cyclam-acetate)FeN3]PF6, 1, has been synthesized, which has been found to have significantly different properties than its unmethylated analogue, [(cyclam-acetate)FeN3]PF6, 2. Whereas the iron ion in 2 is low spin with S = 1/2, 1 is found to be high spin at temperatures above 100 K, though low-spin species are observed at lower temperatures, indicating a spin crossover phenomenon. The iron(II) species 1red is electrochemically more accessible than 2red since the Fe2+/3+ redox wave in 1 appears approximately 350 mV more positive than the corresponding wave in 2. Also, 1 displays a reversible Fe3+/4+ redox wave, which is irreversible in 2, denoting that the Fe(IV) species 1ox is kinetically stable. 1red and 1ox have been generated electrochemically in solution and studied spectroscopically. M?ssbauer spectroscopy has confirmed that, in both reduction and oxidation, iron is the redox center, that 1red is high spin (S = 2), and that 1ox is low spin (S = 1), in contrast to 2red which is low spin and 2ox which could not be isolated. 相似文献
1000.
Summary Inconsistent literature reports on the preparation of the mono- and bis-(trichloroacetic acid)-solvated ferricenium trichloroacetates, (1) and (2) have prompted a comprehensive investigation of the experimental conditions giving rise to the formation of the two ferricenium salts. In agreement with the majority of authors, (2) is reproducibly obtained from trichloroacetic acid and ferrocene in molar ratios of 3 and higher in benzene over a wide range of experimental variables in the presence of air or, preferably, under conditions of oxygen saturation. Treatment of aqueous ferricenium sulfate solutions with trichloroacetic acid in an acid/ferrocene ratio of 3 and above affords the di-solvate, whereas at lower reactant ratios, and under conditions of reduced acidity, formation of the mono-solvate prevails. More efficiently, and in a higher degree of purity, the latter salt is generated from the former by a controlled recrystallization from water. Representative spectroscopic features of the two salts are discussed. 相似文献