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61.
Alexander Zimmermann Qais Z. Jaber Dr. Johannes Koch Steffen Riebe Dr. Cecilia Vallet Dr. Kateryna Loza Matthias Hayduk Dr. Kfir B. Steinbuch Prof. Shirley K. Knauer Prof. Micha Fridman Jun.-Prof. Jens Voskuhl 《Chembiochem : a European journal of chemical biology》2021,22(9):1563-1567
We report the characterization of amphiphilic aminoglycoside conjugates containing luminophores with aggregation-induced emission properties as transfection reagents. These inherently luminescent transfection vectors are capable of binding plasmid DNA through electrostatic interactions; this binding results in an emission “on” signal due to restriction of intramolecular motion of the luminophore core. The luminescent cationic amphiphiles effectively transferred plasmid DNA into mammalian cells (HeLa, HEK 293T), as proven by expression of a red fluorescent protein marker. The morphologies of the aggregates were investigated by microscopy as well as ζ-potential and dynamic light-scattering measurements. The transfection efficiencies using luminescent cationic amphiphiles were similar to that of the gold-standard transfection reagent Lipofectamine® 2000. 相似文献
62.
Johannes Karges Seth M. Cohen 《Chembiochem : a European journal of chemical biology》2021,22(16):2600-2607
The severe acute respiratory syndrome – coronavirus 2 (SARS-CoV-2), the infectious agent responsible for COVID-19 – has caused more than 2.5 million deaths worldwide and triggered a global pandemic. Even with successful vaccines being delivered, there is an urgent need for novel treatments to combat SARS-CoV-2, and other emerging viral diseases. While several organic small molecule drug candidates are in development, some effort has also been devoted towards the application of metal complexes as potential antiviral agents against SARS-CoV-2. Herein, the metal complexes that have been reported to show antiviral activity against SARS-CoV-2 or one of its target proteins are described and their proposed mechanisms of action are discussed. 相似文献
63.
Emerging scanning technologies currently capture diverse data that includes geometrical and physical properties (i.e. normals, material and color). Yet, existing inspection computational methods do not satisfy industry demands. This paper proposes a new approach for inherently handling diverse data and utilizing the synergy between inspection technologies and digital processing methods. Two methods were developed: a Hierarchical Space Decomposition Model (HSDM), which sorts the sampled data, and a 3D Geometrical Bilateral Filter (3D GBF) that utilizes the diverse data. These methods provide efficient data reduction while preserving sharp features. The feasibility of this approach is demonstrated on the diverse data. 相似文献
64.
Johannes C. Jansen Marialuigia Macchione Raniero Mendichi Enrico Drioli 《Polymer》2005,46(25):11366-11379
Asymmetric gas separation membranes were prepared by the dry-casting technique from PEEKWC, a modified amorphous glassy poly(ether ether ketone). The phase inversion process and membrane performance were correlated to the properties of the polymer and the casting solution (molar mass, polymer concentration, solution rheology and thermodynamics). It was found that a broad molar mass distribution of the polymer in the casting solution is most favourable for the formation of a highly selective membrane with a dense skin and a porous sub-layer. Thus, membranes with an effective skin thickness of less than 1 μm were obtained, exhibiting a maximum O2/N2 selectivity of 7.2 and a CO2/CH4 selectivity of 39, both significantly higher than in a corresponding thick dense PEEKWC membrane and also comparable to or higher than that of the most commonly used polymers for gas separation membranes. The CO2 and O2 permeance were up to 9.5×10−3 and 1.8×10−3 m3/(m2 h bar) (3.5 and 0.67 GPU), respectively. 相似文献
65.
66.
In this article we describe our recent efforts in the area of palladium- and nickel-catalysed aromatic substitution reactions. Main focus is on low cost and low waste production methods. The use of aromatic carboxylic anhydrides in the Heck reaction leads to a waste-free protocol. In addition these reactions are easy to work up as no ligands or bases are used. For Heck reactions where substrates or products do not tolerate high temperatures we found that use of a bulky phosphoramidite (13b) as ligand for palladium leads to a very fast reaction at low temperatures. Recycle of palladium in ligand-free Heck and Suzuki reactions is easily accomplished by treating the palladium black that precipitates at the end of the reaction on a carrier material with a small excess of I2 prior to its re-use in the next run. Use of aryl chlorides in the palladium- and nickel-catalysed formation of biaryls can be accomplished by using the nickel-catalysed coupling with arylzinc chlorides. Better still, it was possible to make use of the arylgrignard and use a catalytic amount of ZnCl2. Whereas the strength of these aromatic substitution reactions lies in their broad tolerance of functional groups, one exception was the Sonogashira reaction on 3-bromoaniline. The problem was solved by making use of in situ catalytic protection of the NH2 group with benzaldehyde. 相似文献
67.
Carbon Aerogels as Electrode Material in Supercapacitors 总被引:5,自引:0,他引:5
U. Fischer R. Saliger V. Bock R. Petricevic J. Fricke 《Journal of Porous Materials》1997,4(4):281-285
Due to their large specific surface area and their high electrical conductivity carbon aerogels are promising materials for electrodes in electrochemical double-layer capacitors (supercapacitor). The carbon aerogels were made via pyrolysis of resorcinol formaldehyde aerogels. The latter were prepared by supercritical and subcritical drying as well. The important findings of our investigation were, that the highest capacities of 46 F/cm3 were measured for samples with a density of about 800 kg/m3 pyrolyzed at 800°C. Also it was shown that RF-gels with molar resorcinol/catalyst ratios 1000 or higher can be dried subcritically without cracking or significant shrinkage. Carbon aerogels derived from these RF-aerogels have a small mesopore surface area, however an especially large micropore area. They provide electrical capacities which are most suitable for their use in supercapacitors. 相似文献
68.
In this article, we formulate and study quantum analogues of randomized search heuristics, which make use of Grover search (in Proceedings of the 28th Annual ACM Symposium on Theory of Computing, pp. 212–219. ACM, New York, 1996) to accelerate the search for improved offsprings. We then specialize the above formulation to two specific search heuristics: Random Local Search and the (1+1) Evolutionary Algorithm. We call the resulting quantum versions of these search heuristics Quantum Local Search and the (1+1) Quantum Evolutionary Algorithm. We conduct a rigorous runtime analysis of these quantum search heuristics in the computation model of quantum algorithms, which, besides classical computation steps, also permits those unique to quantum computing devices. To this end, we study the six elementary pseudo-Boolean optimization problems OneMax, LeadingOnes, Discrepancy, Needle, Jump, and TinyTrap. It turns out that the advantage of the respective quantum search heuristic over its classical counterpart varies with the problem structure and ranges from no speedup at all for the problem Discrepancy to exponential speedup for the problem TinyTrap. We show that these runtime behaviors are closely linked to the probabilities of performing successful mutations in the classical algorithms. 相似文献
69.
Naoufal Bahlawane Edgar Fischer Rivera Katharina Kohse-Hinghaus Armin Brechling Ulf Kleineberg 《Applied catalysis. B, Environmental》2004,53(4):245-255
The chemical vapor deposition method was used to deposit thin films of cobalt oxide starting with cobalt (II) acetylacetonate and oxygen. The deposition process was investigated and the obtained films were identified as a cubic spinel-type polycrystalline Co3O4 with a crystallite size of 30–40 nm. The coating was carbon-free and the surface oxygen concentration was measured to be 66 at.% with AES analysis. Smooth and highly uniform thin films were deposited on planar stainless steel substrates and subjected to TPR and catalysis tests that show positive correlation. The apparent activation energy of Co3O4 reduction to CoO was measured to be (33±5) kJ/mol. The catalytic activity of Co3O4 was investigated toward the conversion of both propane and ethanol to carbon dioxide. Though the catalytic action was registered at the same temperature, the deactivation process was seen to be different. The catalytic conversion of ethanol induces a fast deactivation process, which was linked to its high ability to reduce Co3O4. 相似文献
70.
In many studies on lipoxygenase catalysis, nonionic detergents are used to obtain an optically transparent solution of the
fatty acid substrate. In order to resolve some controversies that exist with regard to the interpretation of kinetic data
obtained with solutions containing nonionic detergents, a systematic investigation was undertaken into the effects of Lubrol,
Tween-20 and Triton X-100 (0–0.8 g/L) on the kinetics of linoleate (2.5–110 μM) dioxygenation, catalyzed by lipoxygenase-1
or lipoxygenase-2 from soybean, at pH 9 or 10, at 25°C. Under most conditions, it was found that the detergents slowed down
the reaction. However, at high linoleate concentrations, where substrate inhibition of lipoxygenase is significant, small
amounts of detergent increased the dioxygenation rate. In a quantitative analysis of the results, a kinetic model in which
the incorporation of linoleate in the detergent micelles is formulated as a simple reversible equilibrium, and in which both
lipoxygenase-1 and-2 interact with free linoleate, but not with linoleate incorporated in the micelles, appeared to be sufficient
to predict experimental results over a wide range of experimental conditions. According to this model, the changes in the
dioxygenation kinetics caused by the presence of nonionic detergents are similar (but not equal) to those caused by competitive
inhibitors. The conclusions that monomeric, nonmicellar linoleate is the preferred substrate for lipoxygenase and that the
observed inhibition and stimulation are solely due to changes in the effective linoleate concentration strongly corroborate
the earlier observations by Galpin and Allen [Biochim. Biophys. Acta 488 (1977), 392–401]. 相似文献