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1.
We present the performance of a high-speed gateable vacuum image pipeline, which permits individual images to be delayed and selected from continuous non-repetitive image stream. This device is composed of a vacuum tube equipped with a photocathode at one end, a phosphor screen at the other end, and a system of metal grids in between. Photoelectrons produced by the images focused on the photocathode, are guided by a uniform magnetic field, parallel to the tube axis. By changing the grid potentials, the drift time of the photoelectrons inside the tube can be varied from 0.35 to 1.5 μs. An image can then be selected by an external trigger with a time resolution in the range of 4–30 ns, depending on the delay time. The selected photoelectrons are finally accelerated onto the phosphor screen, set at 10 kV, where they reproduce the desired image. With a magnetic field of 0.1 T, a spatial resolution of 33 lp/mm was obtained. The high spatial and time resolution make this device an interesting tool for high-energy physics and astrophysics experiments, and for high-speed photography.  相似文献   
2.
This work summarizes the progress in the study of the superconductor response to optical radiation and in the development of infrared detectors. The recent advances in the design of high-T c superconducting radiation detectors using silicon microfabrication technology are emphasized. Thermal and optical properties important for the detector performance are discussed. The mechanism of the nonequilibrium optical response and its potential use to build fast and sensitive radiation detectors are described. Future challenges and opportunities in the development of high-T c superconducting radiation detectors are highlighted.  相似文献   
3.
Corrective osteotomy interventions on lower extremities are widely accepted procedures for restoring axial alignment of lower limbs. However, some studies reveal failure rates of up to 70 per cent in a 10 year time frame, which indicates that the success of corrective osteotomies depends on multiple factors. Based on a comprehensive review of error sources among conventional correction osteotomy interventions, a novel approach was developed in order to reduce these error sources among all clinical working steps (deformity determination, planning, and intra-operative realization). The article describes the implemented methodology for realizing optimal correction osteotomies based on a six-dimensional or 12-dimensional optimization module for single- and double-cut oblique osteotomies. The results show that the realized planning and navigation concept enables reduction in the error sources among the clinical working steps of correction osteotomy interventions.  相似文献   
4.
In order to elucidate the effects of metallic La addition on the performance of Ti–V-based hydrogen storage alloys as negative electrodes for nickel/metal-hydrides batteries, Ti0.17Zr0.08-xLaxV0.35Cr0.1Ni0.3 (x = 0, 0.01, 0.02, 0.03, 0.04) alloys were prepared and their structural and electrochemical properties were systematically investigated. X-ray powder diffraction (XRD) results showed that these alloys were mainly consisted of C14 Laves phase with a hexagonal structure, V-based solid solution phase with BCC structure and C15 Laves phase with a cubic structure. The electrochemical measurements indicated that the maximum discharge capacities of the alloy electrodes decreased from 337.3 mAh/g (x = 0) to 262.5 mAh/g (x = 0.04) and that the substitution of Zr with metallic La in the alloys had no obvious effect on the capacity retention rate (C100/Cmax, C200/Cmax). The high-rate dischargeability (HRD) of the alloy electrodes at the discharge current density of 800 mA/g first increased from 69.01% (x = 0) to 71.13% (x = 0.01) and then decreased to 65.35% (x = 0.04). In brief, the HRD was improved with an optimum La content in the alloy (x = 0.01). The electrochemical hydrogen kinetics of the alloy electrodes was further studied by means of electrochemical impedance spectroscopy, linear polarization, anodic polarization and potential-step measurements. The charge-transfer reaction resistance Rct decreased for x = 0.01 with respect to x = 0 and then increased with the increase of x, while exchange current density I0, limiting current density IL and hydrogen diffusion coefficient D were all increased for x = 0.01 with respect to x = 0 and then decreased with the increase of x. The optimal content of La in Ti0.17Zr0.08-xLaxV0.35Cr0.1Ni0.3 alloys for negative electrodes in alkaline rechargeable secondary batteries is x = 0.01 in this study.  相似文献   
5.
Thermophysical and thermochemical property data on organic compounds provide vital background information for scientific and engineering communities in both academic and industrial environments. The Thermodynamics Research Center (TRC) has collected an enormous amount of property data over the past 55 years. New advances in computer technology enable relatively large databases to have friendly communications based upon a PC Windows platform. Here we discuss the structure, upgrade procedures, and mechanisms for distribution over local PC networks and the Internet, with emphasis on three databases: TRC COMPOUNDS (Wincmp), SOURCE (WinSource), the archive of raw experimental data, and TRC TABLE (WinTable), the TRC collection of recommended data.  相似文献   
6.
The authors propose a simple version of the dot-plot scheme to be used in the case when the distances between sequence elements may take more than two values. The method is applicable, in particular, to the case of the sequences of large-length windows when the sets of distance values are continuous. The proposed technique is simple to implement and the results can produce readable maps for further analysis. To illustrate its potentialities, the method has been applied to the comparison of genomic sequences. The asymmetry in the number of direct and reverse tracks for the Homo sapience genome has been discovered.  相似文献   
7.
8.
We report a novel hybrid charge sensor realized by the deposition of phospholipid monolayers on highly doped n‐GaN electrodes. To detect the binding of recombinant proteins with histidine‐tags, lipid vesicles containing chelator lipids were deposited on GaN electrodes pre‐coated with octadecyltrimethoxysilane monolayers. Owing to its optical transparency, GaN allows the confirmation of the fluidity of supported membranes by fluorescence recovery after photo‐bleaching (FRAP). The electrolyte‐(organic) insulator‐semiconductor (EIS) setup enables one to transduce variations in the surface charge density ΔQ into a change in the interface capacitance ΔC p and, thus, the flat‐band potential ΔU FB. The obtained results demonstrate that the membrane‐based charge sensor can reach a high sensitivity to detect reversible changes in the surface charge density on the membranes by the formation of chelator complexes, docking of eGFP with histidine tags, and cancellation by EDTA. The achievable resolution of ΔQ ≥ 0.1 μC/cm2 is better than that obtained for membrane‐functionalized p‐GaAs, 0.9 μC/cm2, and for ITO coated with a polymer supported lipid monolayer, 2.2 μC/cm2. Moreover, we examined the potential application of optically active InGaN/GaN quantum dot structures, for the detection of changes in the surface potential from the photoluminescence signals measured at room temperature.  相似文献   
9.
The study was conducted to report on the use of molecular biology methods and pregnancy outcome in women sensitized to either Rhesus D (RhD) or Kell 1 (K1) antigens. Paternal RhD genotype was determined by DNA amplification of an RhD-specific sequence from single sperm cells. Paternal Kell phenotype was determined by serologic assays using peripheral blood samples, and the fetal RhD or Kell-type status were established by the polymerase chain reaction (PCR) with amniotic cells. Thirteen women (14 pregnancies, one with twins) sensitized to RhD and four sensitized to K1 antigens, comprised the study group. All had paternal heterozygosity to either D or K1 antigens. Nine fetuses were RhD positive and five were RhD negative. An additional woman underwent early spontaneous abortion. The nine RhD-positive fetuses underwent a total of 41 invasive procedures. One fetus with hydrops fetalis died in utero after intrauterine blood transfusion. All the remaining RhD-positive fetuses were delivered after 33 weeks gestation, and all those who were RhD negative were delivered at term. Four women were sensitized to the K1 antigen; in three, the fetus was found to be K1 negative, and in one, K1 positive, necessitating intrauterine blood transfusion. In all cases, the results of RhD or K1 genotype analyses from amniotic fluid were compatible with fetal/neonatal red blood cell RhD or Kell phenotypes. In conclusion, the use of molecular biology techniques represents a major advance in the clinical management of RhD and Kell alloimmunization.  相似文献   
10.
The transmission of ultrashort optical pulses over long distances in optical fibers is limited by pulse broadening due to group velocity dispersion. A grating and telescope dispersion compensator with group velocity dispersion of equal magnitude and opposite sign can compensate for the fiber dispersion. The possible benefits of such dispersion compensation in the 1.3-1.6-μm wavelength region are investigated. The results show that compensation of first-order dispersion at 1.55 μm in a fiber with zero dispersion near 1.3 μm is primarily limited by the second-order dispersion of the grating and the telescope compensator. For a wavelength slightly greater than the zero dispersion wavelength, both the first- and second-order group velocity dispersion can be canceled by the grating and telescope dispersion compensator, allowing transmission exceeding 100 Gb/s over 100 km  相似文献   
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