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51.
52.
Monocrystalline antimony electrodes have been studied by cyclic voltammetry in solutions containing sodium nitrate and one of the following complexing agents: TRIS [Tris (hydroxymethyl) amino methane], orthophosphate, EDTA (ethylenedinitrilo tetraacetic acid) or tartrate at an ionic strength of 0.16 The results have been compared to results obtained in a solution containing only sodium nitrate, which has been shown previously to have no effect on the Sb-electrode potential in the pH range 2–10 which was studied.The results indicate formation of soluble complexes with the ligands studied. Competing reactions seem to take place in the solutions containing orthophosphate (and presumably EDTA). The reactions between Sb(III) and TRIS or orthophosphate seem to be reversible for all practical purposes.The complex formation between Sb(III) and TRIS seems to be weak since the behaviour of the electrode is very similar in TRIS and in pure nitrate solution. TRIS is therefore suitable as a buffer for calibrating antimony electrodes. 相似文献
53.
The mechanical, thermomechanical, electrical and some other properties of polyarylates derived from chloro-bisphenol derivates of chloral and phenol, especially from 2,2-bis(4-hydroxyphenyl)-1,1-dichloroethylene and a mixture of tere- and isophthalic acid dichloride (2:1), were examined. 相似文献
54.
Stanislaw Czamanski 《Papers in Regional Science》1969,23(1):65-78
Some Tentative Conclusions It appears that although national input-output tables cannot be used for purposes of regional studies without considerable adjustments, acceptable results can be achieved by the methods tried on the Washington State table.In order to obtain acceptable results it seems important (1) to exclude the tertiary sectors through aggregation, and (2) to use field surveys in order to obtain input-output coefficients for (a) primary industries and (b) industries in which the regional economy is specialized. Price adjustments and adjustments for domestic imports do not seem to add anything to the quality of results. Neither do successive iterations after the first one.Financial help for this research was provided by a Cornell Faculty Research Grant to the senior author and is acknowledged. The authors are deeply indebted to the late Professor Charles M. Tiebout, of the University of Washington, who provided the Washington State Input-Output Table used for the case study and who also assisted with helpful comments. Mrs. Katherine Drew and Mrs. Tessa Osborne gave programming assistance, and Barry Lawson acted as research assistant during part of the preparation. 相似文献
55.
The aim of these investigations was to determine the effect of the ratio % Mo to % W in the austenite of high-speed steels on the kinetics of its transformation under continuous cooling. The investigations were carried out on model alloys. Three CCT curves were drawn. Also the influence of cooling velocity on the volume fraction of retained austenite in high-speed steels was evaluated. It was determined that with the increase of the Mo content in the high-speed steel matrix the MS temperature decreases and the fraction of retained austenite increases, the development of the bainite transformation decreases and the stability of austenite increases in the range of diffusion transformations. With an increased cooling rate, the volume fraction of retained austenite decreases at first and then it increases. These changes are caused by the precipitation of carbides from undercooled austenite and can give rise to the differences in the content of retained austenite on the cross-section of quenched tools. 相似文献
56.
Valentina Matveeva Alexey Bykov Valentin Doluda Mikhail Sulman Narendra Kumar Stanislaw Dzwigaj Eric Marceau Leonid Kustov Olga Tkachenko Esther Sulman 《Topics in Catalysis》2009,52(4):387-393
In the present work, nanocatalysts prepared on inorganic supports (zeolites) were investigated in d-glucose oxidation and compared to systems supported on polymer (hypercrosslinked polystyrene (HPS)) previously described.
Catalytic activities and selectivities were measured under various reaction conditions. The selectivity of d-glucose oxidation and activity of both Pd-containing zeolites and HPS-Ru were similar (99.7% and TOF 0.013–0.014 mol/(mol Me s)).
Physicochemical analysis X-ray photoelectron spectroscopy, liquid nitrogen physisorption, diffuse reflectance infrared Fourier
transform spectroscopy of adsorbed CO for metal sites evaluation, CD3CN for acid sites evaluation showed that Pd species were in oxidic form, while Ru species were in oxidic and reduced form.
The catalytic activity decreased when acidic sites were present in Pd-containing zeolites. 相似文献
57.
AnaM. Lozano Vila Stijn Monsaert Renata Drozdzak Stanislaw Wolowiec Francis Verpoort 《Advanced Synthesis \u0026amp; Catalysis》2009,351(16):2689-2701
We here report on the stability and catalytic activity of new indenylidene‐Schiff base‐ruthenium complexes 3a – f through representative cross‐metathesis (CM) and ring‐closing metathesis (RCM) reactions. Excellent activity of the new complexes was found for the two selected RCM reactions; prominent conversion was obtained compared to the commercial Hoveyda–Grubbs catalyst 2 . Moreover, excellent results were obtained for a standard CM reaction. Higher conversions were achieved with one of the indenylidene catalysts compared with Hoveyda–Grubbs catalyst. Unexpectedly, an isomerization reaction was observed during the CM reaction of allylbenzene. To the best of our knowledge, isomerization reactions in this model CM reaction in closed systems have never been described using first generation catalysts, including the Hoveyda–Grubbs catalyst. The first model CM reactions as well as the RCM reactions have been monitored using 1H NMR. The course of the CM reaction of 3‐phenylprop‐1‐ene ( 8 ) and cis‐1,4‐diacetoxybut‐2‐ene ( 9 ) was monitored by GC. The isomerization reaction was studied by means of GC‐mass spectrometry and in situ IR spectroscopy. All catalysts were structurally characterized by means of 1H, 13C, and 31P NMR spectroscopy. 相似文献
58.
Piotr Wacinski Mariusz Gadzinowski Wojciech Dabrowski Justyna Szumilo Jakub Wacinski Nathalie Oru Eric Vicaut Stanislaw Czuczwar Janusz Kocki Teresa Basinska Stanislaw Slomkowski 《International journal of molecular sciences》2021,22(14)
Atherosclerosis involves an ongoing inflammatory response of the vascular endothelium and vessel wall of the aorta and vein. The pleiotropic effects of statins have been well described in many in vitro and in vivo studies, but these effects are difficult to achieve in clinical practice due to the low bioavailability of statins and their first-pass metabolism in the liver. The aim of this study was to test a vessel wall local drug delivery system (DDS) using PLA microstructures loaded with simvastatin. Wistar rats were fed high cholesterol chow as a model. The rat vessels were chemically injured by repeated injections of perivascular paclitaxel and 5-fluorouracil. The vessels were then cultured and treated by the injection of several concentrations of poly(L,L-lactide) microparticles loaded with the high local HMG-CoA inhibitor simvastatin (0.58 mg/kg) concentration (SVPLA). Histopathological examinations of the harvested vessels and vital organs after 24 h, 7 days and 4 weeks were performed. Microcirculation in mice as an additional test was performed to demonstrate the safety of this approach. A single dose of SVPLA microspheres with an average diameter of 6.4 μm and a drug concentration equal to 8.1% of particles limited the inflammatory reaction of the endothelium and vessel wall and had no influence on microcirculation in vivo or in vitro. A potent pleiotropic (anti-inflammatory) effect of simvastatin after local SVPLA administration was observed. Moreover, significant concentrations of free simvastatin were observed in the vessel wall (compared to the maximum serum level). In addition, it appeared that simvastatin, once locally administered as SVPLA particles, exerted potent pleiotropic effects on chemically injured vessels and presented anti-inflammatory action. Presumably, this effect was due to the high local concentrations of simvastatin. No local or systemic side effects were observed. This approach could be useful for local simvastatin DDSs when high, local drug concentrations are difficult to obtain, or systemic side effects are present. 相似文献
59.
Stanislaw Osowski 《International Journal of Circuit Theory and Applications》2012,40(9):975-983
This paper presents the application of signal flow graphs (SFG) in the calculation of higher‐order derivatives (sensitivities) of the linear circuit functions. The idea of exact differentiation of the circuit functions is based on the adjoint networks, translated into SFG language. Thanks to its application, it is possible to calculate the exact value of any order derivative of circuit function without knowing this function in explicit form. Moreover, these derivatives can be determined on the basis of analysis of only two graphs (circuits): the original and adjoint one. We show that the SFG approach to the sensitivity calculation allows to reduce greatly the complexity of calculations. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
60.
Stanislaw Stupkiewicz 《International journal for numerical methods in engineering》2001,50(3):739-759
A class of friction laws depending on the measure of contact surface expansion is defined in the paper within the continuum contact mechanics framework. The nominal and spatial forms of constitutive relations are discussed, including incremental penalty relations. Further, an extended node‐to‐segment element is derived which is capable of treating surface‐expansion‐dependent contact laws in a consistent way. The approach is suitable for any kind of node‐to‐segment contact elements. Finally, the computational efficiency of the extended element as well as other possible approaches are illustrated by numerical examples relevant to metal forming applications. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献