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651.
Equivalency of Lightning Return-Stroke Models Employing Lumped and Distributed Current Sources 总被引:1,自引:0,他引:1
Grzegorz Maslowski Vladimir A. Rakov 《Electromagnetic Compatibility, IEEE Transactions on》2007,49(1):123-132
We show that any engineering return-stroke model can be expressed, using an appropriate continuity equation, in terms of either lumped or distributed current sources with the resultant longitudinal-current distribution along the channel being the same. This property can be viewed as the duality of engineering models. The conversion alters the actual-corona current (if any) of the model. For lumped-source (LS) models the actual-corona current is unipolar and directed radially out of the channel core, while for distributed-source (DS) models it is unipolar and directed into the channel core. For LS models converted to DS models and for the Diendorfer-Uman (DU) model converted to the equivalent LS model, the corona current is the sum of the negated actual-corona current (if any) and a fictitious-corona current, the latter being bipolar. For the transmission-line (TL) model (no longitudinal current attenuation with height) expressed in terms of DSs, there is only a fictitious bipolar corona current component. Conversion of the traveling-current source (TCS) and Bruce-Golde (BG) models to equivalent LS models involves replacement of the actual, unipolar corona current with a fictitious one, the latter current being bipolar near the channel base and unipolar at higher altitudes 相似文献
652.
A Tool for Prioritizing DAGMan Jobs and its Evaluation 总被引:1,自引:0,他引:1
Grzegorz Malewicz Ian Foster Arnold L. Rosenberg Michael Wilde 《Journal of Grid Computing》2007,5(2):197-212
It is often difficult to perform efficiently a collection of jobs with complex job dependencies due to temporal unpredictability
of the Grid. One way to mitigate the unpredictability is to schedule job execution in a manner that constantly maximizes the
number of jobs that can be sent to workers. A recently developed scheduling theory provides a basis to meet that optimization
goal. Intuitively, when the number of such jobs is always large, high parallelism can be maintained, even if the number of
workers changes over time in an unpredictable manner. In this paper we present the design, implementation, and evaluation
of a practical scheduling tool inspired by the theory. Given a DAGMan input file with interdependent jobs, the tool prioritizes
the jobs. The resulting schedule significantly outperforms currently used schedules under a wide range of system parameters,
as shown by simulation studies. For example, a scientific data analysis application, AIRSN, was executed at least 13% faster
with 95% confidence. An implementation of the tool was integrated with the Condor high-throughput computing system.
The research of G. Malewicz was supported in part by NSF Grant ITR-800864. The research of I. Foster and M. Wilde was supported
in part by the NSF GriPhyN project and by the Mathematical, Information, and Computational Sciences Division subprogram of
the Office of Advanced Scientific Computing Research, U.S. Department of Energy, under Contract W-31-109-Eng-38. The research
of A.L. Rosenberg was supported in part by NSF Grant CCF-0342417. 相似文献
653.
Yu H.Y. Chang S.Z. Veloso A. Lauwers A. Adelmann C. Onsia B. Lehnen P. Kauerauf T. Brus S. Yin K.M. Absil P. Biesemans S. 《Electron Device Letters, IEEE》2007,28(11):957-959
This letter reports a novel approach to achieve low threshold voltage (Vt) Ni-fully-silicide (FUSI) nMOSFETs with SiON dielectrics. By using a dysprosium-oxide (Dy2O3) cap layer with a thickness of 5 Aring on top of the SiON host dielectrics, Vt,lin of 0.18 V for long-channel devices (Lg = 1 mum) using NiSi-FUSI electrode is obtained, satisfying the high-performance device requirements. The Vt modulation due to the Dy2O3 cap layer is also maintained in the short-channel devices (with an Lg,min of 90 nm as demonstrated in this letter). In particular, approximately 150times reduction in gate leakage current is seen while preserving the dielectric capacitance equivalent thickness after adding the Dy2O3 cap layer on SiON dielectrics, likely due to a high-k layer (DySiON) formation during device source/drain activation process. We also report that the Dy2O3 layer does not vitally degrade the device reliability, such as positive-bias temperature instability and time-dependant dielectrics breakdown. 相似文献
654.
Micha Marcinkowski Toma Pilys Damian Garbicz Jan Piwowarski Damian Mielecki Grzegorz Nowaczyk Micha Taube Maciej Gielnik Maciej Kozak Maria Winiewska-Szajewska Ewa Szoajska Janusz Dbski Agnieszka M. Maciejewska Kaja Przygoska Karolina Ferenc Elbieta Grzesiuk Jarosaw Poznaski 《International journal of molecular sciences》2021,22(9)
The FTO protein is involved in a wide range of physiological processes, including adipogenesis and osteogenesis. This two-domain protein belongs to the AlkB family of 2-oxoglutarate (2-OG)- and Fe(II)-dependent dioxygenases, displaying N6-methyladenosine (N6-meA) demethylase activity. The aim of the study was to characterize the relationships between the structure and activity of FTO. The effect of cofactors (Fe2+/Mn2+ and 2-OG), Ca2+ that do not bind at the catalytic site, and protein concentration on FTO properties expressed in either E. coli (ECFTO) or baculovirus (BESFTO) system were determined using biophysical methods (DSF, MST, SAXS) and biochemical techniques (size-exclusion chromatography, enzymatic assay). We found that BESFTO carries three phosphoserines (S184, S256, S260), while there were no such modifications in ECFTO. The S256D mutation mimicking the S256 phosphorylation moderately decreased FTO catalytic activity. In the presence of Ca2+, a slight stabilization of the FTO structure was observed, accompanied by a decrease in catalytic activity. Size exclusion chromatography and MST data confirmed the ability of FTO from both expression systems to form homodimers. The MST-determined dissociation constant of the FTO homodimer was consistent with their in vivo formation in human cells. Finally, a low-resolution structure of the FTO homodimer was built based on SAXS data. 相似文献
655.
Viktor V. Brus Jaewon Lee Benjamin R. Luginbuhl Seo‐Jin Ko Guillermo C. Bazan Thuc‐Quyen Nguyen 《Advanced materials (Deerfield Beach, Fla.)》2019,31(30)
Recent research efforts on solution‐processed semitransparent organic solar cells (OSCs) are presented. Essential properties of organic donor:acceptor bulk heterojunction blends and electrode materials, required for the combination of simultaneous high power conversion efficiency (PCE) and average visible transmittance of photovoltaic devices, are presented from the materials science and device engineering points of view. Aspects of optical perception, charge generation–recombination, and extraction processes relevant for semitransparent OSCs are also discussed in detail. Furthermore, the theoretical limits of PCE for fully transparent OSCs, compared to the performance of the best reported semitransparent OSCs, and options for further optimization are discussed. 相似文献
656.
Martina Cazzola Jacopo Barberi Sara Ferraris Andrea Cochis Grzegorz Cempura Aleksandra Czyrska-Filemonowicz Lia Rimondini Silvia Spriano 《Advanced Engineering Materials》2023,25(2):2200883
This research aims toward an antibacterial and osteoconductive Ti6Al4V surface by chemical etching–oxidation treatment and in situ reduction of silver nanoparticles. Starting from a previously developed process, already proved to enhance the osteoinductive ability of titanium, different parameters are changed to tailor the amount of silver and its distribution across the surface oxide layer thickness. The samples are characterized by scanning and transmission electron microscopy, energy-dispersive X-ray spectroscopy, release of silver, biofilm formation (Staphylococcus aureus), and cytocompatibility toward human osteoblasts progenitor cells. The total amount of silver in the surface oxide layer depends only on the concentration of the silver precursor. The time of the addition of the silver precursor, during the oxidation treatment, affects the oxide layer thickness, dimension, and distribution of the nanoparticles across the surface oxide: they are larger and accumulate on the outermost layer, if the addition occurs early. The maximum ion release occurs after 24 h and lasts up to 14 days; the later addition of silver precursors leads to sustaining the silver release for a longer time. The samples prepared with the higher concentration of the silver precursor are bactericide, but highly cytotoxic, whereas the other ones are bacteriostatic and moderately cytotoxic. 相似文献
657.
Grzegorz Mlostoń Róża Hamera-Fałdyga Katarzyna Urbaniak Wolfgang Weigand Heinz Heimgartner 《Journal of Sulfur Chemistry》2018,39(5):516-524
Ferrocenyl thioketones bearing a hetaryl, phenyl or alkyl group as the second substituent react with (trimethylsilyl)diazomethane at ca. ?30°C in THF solution without formation of a stable [3?+?2]-cycloadduct. After the spontaneous evolution of N2, the corresponding sterically crowded 4,4,5,5-tetrasubstituted 2-silylated 1,3-dithiolanes are formed as products of the second [3?+?2]-cycloaddition of the intermediate thiocarbonyl S-methanide with the starting thioketone. After desilylation by treatment with TBAF, they are converted into the corresponding carbanions, which display different stability depending on the type of substituent. The presence of hetaryl and phenyl groups results in the exclusive formation of 1,2-diferrocenyl ethylenes. In contrast, the presence of methyl groups significantly enhances the stability of the carbanion, which by protonation yields trans-4,5-diferrocenyl-4,5-dimethyl-1,3-dithiolane. 相似文献
658.
张博文 颜伟 李兆峰 白龙 Grzegorz Cywinski Ivan Yahniuk Krzesimir Szkudlarek Czeslaw Skierbiszewski Jacek Przybytek Dmytro B. But Dominique Coquillat Wojciech Knap 杨富华 《红外与毫米波学报》2018,37(4):389-392
在场效应晶体管太赫兹探测器中,合理的天线设计可以增强晶体管和太赫兹波之间的耦合效率,从而提高太赫兹探测器的响应度.提出一种基于晶体管栅极边缘沟道电场的仿真来设计平面天线的方法.这种方法尤其适用于太赫兹波段晶体管输入阻抗不容易得到的情况.通过流片完成的基于氮化镓高电子迁移率晶体管的太赫兹探测器的响应度测试证实了这种方法的有效性.集成碟形天线和双偶极子天线的太赫兹探测器最大响应度分别在170.7 GHz(1568.4 V/W)和124.3 GHz(1047.2 V/W)频点处测得,这个测试结果接近基于晶体管栅极边缘沟道电场的仿真结果. 相似文献
659.
M. N. Solovan G. O. Andrushchak A. I. Mostovyi T. T. Kovaliuk V. V. Brus P. D. Maryanchuk 《Semiconductors》2018,52(2):236-241
Graphite/p-SiC Schottky diodes are fabricated using the recently suggested technique of transferring drawn graphite films onto p-SiC single-crystal substrates. The current–voltage and capacitance–voltage characteristics are measured at different temperatures and at different frequencies of a small-signal AC signal, respectively. The temperature dependences of the potential-barrier height and of the series resistance of the graphite/p-SiC junctions are measured and analyzed. The dominant mechanisms of the charge–carrier transport through the diodes are determined. It is shown that the dominant mechanisms of the transport of charge carriers through the graphite/p-Si Schottky diodes at a forward bias are multi-step tunneling recombination and tunneling described by the Newman formula (at high bias voltages). At reverse biases, the dominant mechanisms of charge transport are the Frenkel–Poole emission and tunneling. It is shown that the graphite/p-SiC Schottky diodes can be used as detectors of ultraviolet radiation since they have the open-circuit voltage Voc = 1.84 V and the short-circuit current density Isc = 2.9 mA/cm2 under illumination from a DRL 250-3 mercury–quartz lamp located 3 cm from the sample. 相似文献
660.
Removal of chromium(VI) ions and their reduction were studied on the anion exchanger Dowex PSR-2 in the pH range from 1.5 to 10. The parameters of Cr(VI) sorption process on the anion exchanger were calculated based on the most popular isotherm models such as: Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich (D-R). The Langmuir isotherm was the most appropriate to describe Cr(VI) sorption. The Cr(VI) uptake by Dowex PSR-2 was found to follow the pseudo-second-order rate kinetics. Reduction of chromium(VI) in the pH range 1.5–10 was observed using the HPLC-ICP-MS (high-performance liquid chromatography–inductively coupled plasma-mass spectrometry) method. Oxidation of tri-n-butyl quaternary ammonium groups during the chromate (VI) removal process was observed. 相似文献