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71.
A scanning confocal microscope was used to investigate the spatial positions of specific regions within blood cell nuclei. These centromeric regions were fluorescently labelled by in-situ hybridization to suspended nuclei with a centromere-1-specific DNA probe. The 3-D image data sets, obtained by optical sectioning of the cells, were used to determine the spatial position of the centromeric regions in the nuclei by means of specially developed software. The centromeres were found to be localized near the nuclear boundary. This spatial pattern was tested against a random distribution model by means of the Kolmogorov—Smirnov test. The difference between the two patterns was at a P < 0?01 significance level.  相似文献   
72.
An analytical solution is presented showing the average bit error probability for the land mobile satellite channel. The channel is modelled as Rice and Rayleigh—lognormal fading. Modulation schemes under consideration include differentially detected PSK and non-coherently detected FSK. Results indicate that the receiver performance is highly dominated by the time share of shadowing. The ratio of the BERs in shadowed and unshadowed areas of typical measured channels and an operating point assumed to be at Es/No = 10 dB is of the order of 10?2.  相似文献   
73.
The load—strength theory is used to simulate the movements of a mechanical mechanism consisting of a lever and a spring. The purpose of the mechanism is automatically to select the correct speed for a turntable depending on the size (weight) of the record. The procedure for the computation is given in detail.  相似文献   
74.
During the microstructural examination of ceramic thermal barrier coatings by transmission electron microscopy (TEM), initial efforts for the preparation of cross-sectional thin foils from interface regions by conventional means were mostly failures. Delamination of the Y2O3-stabilized ZrO2 ceramic coating from the nickel-base alloy substrate sometimes occurred during fine polishing at around 80 μm thickness but mostly occurred during dimpling. Because of this sensitivity, special techniques for mechanical handling were developed so that ion milling could give thin enough regions of the metal-ceramic interface. TEM showed convincingly that the highly fragile nature of the coatings is in fact due to the extensive porosity at the interface developed as a result of heat treatment.  相似文献   
75.
It is all too easy to be optimistic about the economic and social future of Latin America. Daniela Fabricius , the author of 100% Favela: The Informal Geographies of Rio de Janeiro (forthcoming), calls into question architects working within the realpolitik of a globalised, post-nationalist world. Could an all too ready acceptance of existing conditions and the adoption of informality leave inhabitants short-changed? For to live informally is also to live precariously - no substitute for secure and prosperous living.  相似文献   
76.
Using a two-dimensional frictional force microscope, we studied the two-dimensional nature of the atomic scale friction between a Si3N4 sharp tip and a cleaved graphite surface, which is composed of only C atoms and is a good conductor. As a result, we observed the two-dimensionally quantized friction with the lattice periodicity of the graphite surface, similarly to mica, MoS2 and NaF surfaces. Thus quantized friction occurs at material surfaces which are composed of not only some elements but also of a single element, and the quantized friction does not depend on the conductivity of the surface.  相似文献   
77.
We introduce co‐variation analysis as a tool for modeling the way part geometries and configurations co‐vary across a family of man‐made 3D shapes. While man‐made 3D objects exhibit large geometric and structural variations, the geometry, structure, and configuration of their individual components usually do not vary independently from each other but in a correlated fashion. The size of the body of an airplane, for example, constrains the range of deformations its wings can undergo to ensure that the entire object remains a functionally‐valid airplane. These co‐variation constraints, which are often non‐linear, can be either physical, and thus they can be explicitly enumerated, or implicit to the design and style of the shape family. In this article, we propose a data‐driven approach, which takes pre‐segmented 3D shapes with known component‐wise correspondences and learns how various geometric and structural properties of their components co‐vary across the set. We demonstrate, using a variety of 3D shape families, the utility of the proposed co‐variation analysis in various applications including 3D shape repositories exploration and shape editing where the propagation of deformations is guided by the co‐variation analysis. We also show that the framework can be used for context‐guided orientation of objects in 3D scenes.  相似文献   
78.
Multivariate graphs are prolific across many fields, including transportation and neuroscience. A key task in graph analysis is the exploration of connectivity, to, for example, analyze how signals flow through neurons, or to explore how well different cities are connected by flights. While standard node‐link diagrams are helpful in judging connectivity, they do not scale to large networks. Adjacency matrices also do not scale to large networks and are only suitable to judge connectivity of adjacent nodes. A key approach to realize scalable graph visualization are queries: instead of displaying the whole network, only a relevant subset is shown. Query‐based techniques for analyzing connectivity in graphs, however, can also easily suffer from cluttering if the query result is big enough. To remedy this, we introduce techniques that provide an overview of the connectivity and reveal details on demand. We have two main contributions: (1) two novel visualization techniques that work in concert for summarizing graph connectivity; and (2) Graffinity, an open‐source implementation of these visualizations supplemented by detail views to enable a complete analysis workflow. Graffinity was designed in a close collaboration with neuroscientists and is optimized for connectomics data analysis, yet the technique is applicable across domains. We validate the connectivity overview and our open‐source tool with illustrative examples using flight and connectomics data.  相似文献   
79.
目的 研究整体包装件跌落时内装PET光栅包装盒的安全性,根据跌落过程中力的传递方式和受力部位进行有效缓冲防护,达到节约包装成本的目的.方法 将质量为10 kg的包装件在高度0.61 m下进行跌落冲击试验,基于试验数据获得包装盒、泡沫衬垫的冲击加速度、跌落变形量参数.结果 得到了包装盒、泡沫衬垫在跌落冲击过程中冲击力的变化规律,泡沫衬垫吸收了大量冲击,延长了冲击脉冲接触时间,减少了传递到包装盒上的冲击力.结论 包装件发生跌落时,泡沫衬垫开始被压缩、吸收外部冲击力,保护内部包装盒,在反弹阶段包装盒遭受的损害大于碰撞初期.结果 显示,在泡沫衬垫和外瓦楞纸箱的缓冲保护作用下,包装盒在0.61 m的高度进行跌落是安全可靠的.  相似文献   
80.
Current techniques used to produce carbon micro-ribbon targets 5 μm wide×3.7–4.5 μg/cm2×25-mm long will be described. Developmental emphasis was to provide nearly identical micro-ribbons with the minimum number of atoms per unit of length, and to position them within ±0.5 mm of the desired location on C-shaped frames.The foil strip targets to be described were 200–600 μm wide×3.7–4.5 μg/cm2×51 mm long. These were produced from 25-mm-wide carbon film deposits that were scribed using a jig prior to dissolving the betaine/sucrose release agent under ethanol.Both types of targets required methods and devices that differed significantly from those reported previously for substrate texturing, masking, vacuum deposition, releasing from the substrate, and mounting. Sets of 12–24 of the targets have been made for the 2006 run period at BNL.  相似文献   
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