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991.
This study examined different types of longitudinal associations (i.e., directional links and overlapping developmental changes) between children's delinquency and the quality of parent–child relationships from middle childhood to late adolescence. We used 10-wave interview data of 503 boys, their primary caregivers, and their teachers. Our first aim was to unravel the direction of effects between parent–child relationships and children's offending. Cross-lagged panel models revealed bidirectional links over time between poorer quality parent–child relationships and boys' offending across late childhood (age 7–10), early adolescence (age 10–13) and middle adolescence (age 13–16). Second, we examined the associations between mean changes in delinquency, on the one hand, and mean changes in relationship quality, on the other hand. Although parent–child relationships improved during childhood, their quality decreased in early adolescence and remained stable in middle adolescence. Delinquency increased only in middle adolescence. In five out of six models, the slope factors of relationship quality and offending were strongly correlated, indicating that stronger increases in delinquency were associated with stronger decreases in parent–child relationship quality across childhood, early adolescence, and middle adolescence. The discussion focuses on the theoretical implications of these two types of longitudinal associations. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
992.
吴安官 《供用电》2011,28(2):1-4
对电力系统较长时间段的最小、正常、最大三种负荷方式的合理划分,是目前电力网技术经济问题中急需解决的重要问题。参照计划评审技术与概率倍加原则,对持续负荷曲线及其平方曲线进行关联分析,利用持续负荷曲线洛桑德(Rossander)公式计算了最小、正常、最大三种负荷方式的两个功率分点,得到了计算公式,构建了较长时段三种负荷方式区段划分的新方法;以一个算例说明三种负荷方式划分计算过程和应用的意义。  相似文献   
993.
Digital systems offer computational power and instant feedback. Game designers are using these features to create scaffolding tools to reduce player frustration. However, researchers are finding some unexpected effects of scaffolding on strategy development and problem-solving behaviors. We used a digital Sudoku game named Professor Sudoku to classify built-in critical features, frustration control and demonstration scaffolds, and to investigate their effects on player/learner behaviors. Our data indicate that scaffolding support increased the level at which puzzles could be solved, and decreased frustration resulting from excessive numbers of retries. However, it also reduced the number of unassisted placements (i.e., independently filled cells), and increased reliance on scaffolding tools, both of which are considered disadvantageous for learning. Among the three scaffold types, frustration control reduced the potential for players to feel stuck at certain levels, but also reduced the frequency of use of critical feature-making tools, which are thought to have greater heuristic value. We conclude that the simultaneous provision of critical feature and frustration control scaffolds may increase player reliance on available support, thereby reducing learning opportunities. Providing players with critical features and demonstration scaffolds at the same time increases reliance on available support for some players, but for most it encourages the development of solving strategies.  相似文献   
994.
This paper describes the flexibility of Personal Response Systems (PRSs), (also known as ‘clickers’ or electronic voting systems (EVS)), as part of strategies to support students’ learning in science. Whilst variants of this technology began to appear 12 years ago, there is now a steadily increasing adoption of these systems within higher education, including science programmes, and this use has grown significantly in the last six years. They have previously been shown to offer a measurable learning benefit. Typically, someone at an institution buys these systems for learning support and they never make it out of their cases. Far less work has been done with these systems at school level. In this practitioner based paper, the broad range of practical uses for these systems is described in a variety of formal and informal learning situations – from testing the understanding of science concepts (from primary aged school children up to physics undergraduates), to undertaking evaluation of events as well as public participation in data collection for research on attitudes to careers. In addition, the data collected on such handsets can be mapped to demographic factors such as gender and age yielding further layers of analysis. Overall this is a highly flexible and transferable approach to the use of interactive technology for engaging learners of all ages as well as carrying out research.  相似文献   
995.
张鹏  曹庭琪 《冶金设备》2011,(Z1):116-117
针对精轧机组出口板坯头部浪形不达标的问题,采用实测轧机弹跳曲线的方法找出了轧机的机械推上系统间隙无法有效消除是产生浪形不达标的主要原因。根据实际情况提出改造方案,结果表明其有效性。  相似文献   
996.
We introduce a new technique called Implicit Brushes to render animated 3D scenes with stylized lines in realtime with temporal coherence. An Implicit Brush is defined at a given pixel by the convolution of a brush footprint along a feature skeleton; the skeleton itself is obtained by locating surface features in the pixel neighborhood. Features are identified via image‐space fitting techniques that not only extract their location, but also their profile, which permits to distinguish between sharp and smooth features. Profile parameters are then mapped to stylistic parameters such as brush orientation, size or opacity to give rise to a wide range of line‐based styles.  相似文献   
997.
Estimating technological progress of emerging technologies such as renewables and clean coal technologies becomes important for designing low carbon energy systems in future and drawing effective energy policies. Learning curve is an analytical approach for describing the decline rate of cost and production caused by technological progress as well as learning. In the study, a bottom-up energy-economic model including an endogenous technological learning function has been designed. The model deals with technological learning in energy conversion technologies and its spillover effect. It is applied as a feasibility study of clean coal technologies such as IGCC (Integrated Coal Gasification Combined Cycle) and IGFC (Integrated Coal Gasification Fuel Cell System) in Japan. As the results of analysis, it is found that technological progress by learning has a positive impact on the penetration of clean coal technologies in the electricity market, and the learning model has a potential for assessing upcoming technologies in future.  相似文献   
998.
深部开采复合顶板离层稳定性判别   总被引:3,自引:0,他引:3  
为研究深部开采复合顶板力学机理,分析离层稳定性判别标准及依据,采用数值模拟方法分析了不同条件复合顶板结构面剪应力、法向拉应力和离层分布特点.结果表明:法向拉应力是结构面中部离层的主要原因,可用法向拉应力作用范围作为结构面离层范围,并作为离层稳定性判别标准,结构面离层范围及其离层值分布具有相关性,结构面离层范围扩展使结构面不同位置离层值分布趋于均匀,但对结构面最大离层值影响并不显著,以离层值作为离层稳定性判据时,应采用允许离层范围两端离层实测值与临界值进行比较来判别.  相似文献   
999.
结合实际工程,介绍了该应用的具体步骤。通过对工程的分析,绘制了网络图,找到了关键线路,并对工程计划进行了优化。  相似文献   
1000.
Recent 3D sketch tools produce networks of three‐space curves that suggest the contours of shapes. The shapes may be non‐manifold, closed three‐dimensional, open two‐dimensional, or mixed. We describe a system that automatically generates intuitively appealing piecewise‐smooth surfaces from such a curve network, and an intelligent user interface for modifying the automatically chosen surface patches. Both the automatic and the semi‐automatic parts of the system use a linear algebra representation of the set of surface patches to track the topology. On complicated inputs from ILoveSketch [ [BBS08] ], our system allows the user to build the desired surface with just a few mouse‐clicks.  相似文献   
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