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1.
The proposed plasma lens experiment at the Final focus Test Beam (FFTB) facility of the Stanford Linear Accelerator Center has been approved by the adminstration. The experiment would allow the examination of plasma focusing devices for particle beams in the parameter regime of interest to future high-energy colliders. It is expected to lead to compact plasma lens designs capable of focusing the beam to unprecedented small spot sizes.  相似文献   
2.
Mechanical stimuli have been shown to enhance chondrogenesis on both animal and human chondrocytes cultured in vitro. Different mechanical stimuli act simultaneously in vivo in cartilage tissue and their effects have been extensively studied in vitro, although often in a separated manner. A new bioreactor is described where different mechanical stimuli, i.e. shear stress and hydrostatic pressure, can be combined in different ways to study the mechanobiology of tissue engineered cartilage. Shear stress is imposed on cells by forcing the culture medium through the scaffolds, whereas a high hydrostatic pressure up to 15 MPa is generated by pressurizing the culture medium. Fluid-dynamic experimental tests have been performed and successful validation of the bioreactor has been carried out by dynamic culture of tissue-engineered cartilage constructs. The bioreactor system allows the investigation of the combined effects of different mechanical stimuli on the development of engineered cartilage, as well as other possible three-dimensional tissue-engineered constructs.  相似文献   
3.
This paper considers motion control for a cooperative system of automated passenger vehicles. It develops a cooperative scheme based on a decentralized planning algorithm which considers the vehicles in an initial open chain configuration. In this scheme the trajectories are intersections-free, and each trajectory is planned independently of the others. To ensure the stabilization of each vehicle in the planned trajectory, a fuzzy closed loop motion control is presented, where, based on the properties of the Fuzzy maps, the Lyapunov’s stability of the motion errors is demonstrated for all the vehicles. Based on the ISO 2631-1 standard, the saturation property of the Fuzzy maps guarantees low values of longitudinal and lateral accelerations, to ensure comfort of the human body during the motion. The validity of this control algorithm is supported by simulation experiments.  相似文献   
4.
We address the problem of verifying planning domains as used in model-based planning, for example in space missions. We propose a methodology for testing flight rules of planning domains which is self-contained, in the sense that flight rules are verified using a planner and no external tools are required. We review and analyse coverage conditions for requirements-based testing, and we reason in detail on "Unique First Cause" (UFC) coverage for test suites. We characterise flight rules using patterns, encoded using LTL, and we provide UFC coverage for them. We then present a translation of LTL formulae into planning goals, and illustrate our approach on a case study.  相似文献   
5.
Polyphosphonates, polyphosphates, polyarylazophosphonates and polyarylazophosphates were synthesized by a new alternative to the classical phase transfer catalysis, respectively, the modified inverse phase transfer catalysis (IPTC) polycondensation of various phenylphosphonic (phosphoric) dichlorides (phenylphosphonic dichloride, phenylphosphoric dichloride, p-chlorophenylphosphoric dichloride) with bisphenols: bisphenol A, tetrabromobisphenol A, bis-(4-hydroxyphenyl)methane (bisphenol F), 4,4′-dihydroxyazobenzene. The polymers were characterized by infrared spectroscopy and magnetic resonance (1H-NMR, 31P-NMR, 13C-NMR) spectroscopy. Yields in the range of 63.5–85% and molecular weights (M w) of ~2,000–8,200 g mol?1 were obtained. Polyphosphonates were stable up 210–270 °C and polyphosphates up 190–220 °C in air atmosphere. For a correct estimation of the thermal behavior of similar compounds, a kinetic analysis using a modified version of Non Parametric Kinetic method for representative polyphosphonate and polyphosphate was realized. The studies made on the hydrolytic degradation of the synthesized polyphosphates show that the most stable polymer under alkali-catalyzed degradation is the polyphosphate obtained by IPTC of phenylphosphoric dichloride and bisphenol A.  相似文献   
6.
The retinal pigmented epithelium (RPE) plays a pivotal role in retinal homeostasis. It is therefore an interesting target to fill the unmet medical need of different retinal diseases, including age-related macular degeneration and Stargardt disease. RPE replacement therapy may use different cellular sources: induced pluripotent stem cells or embryonic stem cells. Cells can be transferred as suspension on a patch with different surgical approaches. Results are promising although based on very limited samples. In this review, we summarize the current progress of RPE replacement and provide a comparative assessment of different published approaches which may become standard of care in the future.  相似文献   
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8.
Fluorescence lidar imaging of historical monuments   总被引:2,自引:0,他引:2  
What is believed to be the first fluorescence imaging of the facades of a historical building, which was accomplished with a scanning fluorescence lidar system, is reported. The mobile system was placed at a distance of ~60 m from the medieval Lund Cathedral (Sweden), and a 355-nm pulsed laser beam was swept over the stone facades row by row while spectrally resolved fluorescence signals of each measurement point were recorded. By multispectral image processing, either by formation of simple spectral-band ratios or by use of multivariate techniques, areas with different spectral signatures were classified. In particular, biological growth was observed and different stone types were distinguished. The technique can yield data for use in facade status assessment and restoration planning.  相似文献   
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10.
A silver-acrylate nanocomposite was prepared using a novel one-pot strategy involving eosin dye as visible sensitizer and an amine derivative as radicals' source. The mechanism highlighted by steady state photolysis and time-resolved absorption spectroscopy lies on the initial formation of a strong ion-pair complex between eosin and Ag+. Upon visible irradiation, the excited triplet state of the metal complex efficiently abstracts a hydrogen atom from the amine and produces an α-aminoalkyl radical. In acrylate monomer matrix, such a strong reactive species initiates a free radical photopolymerization and also provides the reduction of the silver cation. Through this ‘in-situ’ fabrication method, the kinetics formation of the nanocomposite and its detailed structural analysis are characterized by UV-visible, real-time FTIR absorption spectroscopy and by transmission electron microscopy.  相似文献   
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