首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   116篇
  免费   8篇
化学工业   28篇
建筑科学   4篇
轻工业   4篇
水利工程   1篇
无线电   9篇
一般工业技术   12篇
冶金工业   28篇
自动化技术   38篇
  2023年   1篇
  2022年   1篇
  2021年   6篇
  2020年   1篇
  2019年   2篇
  2018年   3篇
  2016年   8篇
  2015年   3篇
  2014年   6篇
  2013年   10篇
  2012年   9篇
  2011年   4篇
  2010年   7篇
  2009年   7篇
  2008年   13篇
  2007年   6篇
  2006年   6篇
  2005年   2篇
  2004年   2篇
  2003年   2篇
  2002年   3篇
  2001年   5篇
  1999年   4篇
  1998年   2篇
  1997年   2篇
  1995年   2篇
  1989年   1篇
  1986年   2篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
排序方式: 共有124条查询结果,搜索用时 31 毫秒
1.
Analysis of advertisements in Israeli newspapers over the past decade has shown that American symbols have been widely used to market an array of consumer goods. Products made in America, Israel, or other countries are marketed with some sort of American angle by invoking America's values, symbols, landscapes, or lifestyle. Using both qualitative and quantitative methods, we analyzed how central components of the nation-state/national sphere—language, flag, political leaders, borders, landscapes, and sights—are reflected in advertising. We attempt to show how social values metamorphose, shedding their "Israeliness" and taking on an American veneer. Using Israel as an example may provide a test case for the Americanization process in other societies at the turn of the millennium.  相似文献   
2.
Fertigation for minimizing environmental pollution by fertilizers   总被引:2,自引:0,他引:2  
Intensification of agriculture by irrigation and enhanced use of fertilizers may generate pollution by increased levels of nutrients in underground and surface waters. Most of the irrigation is by open systems having a relatively low efficiency of water application. A higher efficiency may be gained by pressurized irrigation systems. Drip irrigation generates a restricted root system requiring frequent nutrient supply that may be satisfied by applying fertilizers in irrigation water, i.e. by fertigation. Maximization of crop yield and quality and minimization of leaching below the rooting volume may be achieved by managing fertilizers concentrations in measured quantities of irrigation water, according to crop requirements.  相似文献   
3.
We present in this paper BP-QL, a novel query language for querying business processes. The BP-QL language is based on an intuitive model of business processes, an abstraction of the emerging BPEL (business process execution language) standard. It allows users to query business processes visually, in a manner very analogous to how such processes are typically specified, and can be employed in a distributed setting, where process components may be provided by distinct providers.  相似文献   
4.
International Journal of Computer Vision - Machine learning models are known to perpetuate and even amplify the biases present in the data. However, these data biases frequently do not become...  相似文献   
5.
The complex hierarchical structure of lamellar bone makes understanding structure–mechanical function relations, very difficult. We approach the problem by first using the relatively simple structure of parallel-fibred bone to construct a mathematical model for calculating Young's moduli in three-dimensions. Parallel-fibred bone is composed essentially of arrays of mineralized collagen fibrils, which are also the basic structural motif of the individual lamellae of lamellar bone. Parallel-fibred bone structure has orthotropic symmetry. As the sizes and shapes of crystals in bone are not well known, the model is also used to compare the cases of platelet-, ribbon- and sheet-reinforced composites. The far more complicated rotated plywood structure of lamellar bone results in the loss of the orthotropic symmetry of individual lamellae. The mathematical model used circumvents this problem by sub-dividing the lamellar unit into a thin lamella, thick lamella, transition zone between them, and the recently observed back-flip lamella. Each of these is regarded as having orthotropic symmetry. After the calculation of their Young's moduli they are rotated in space in accordance with the rotated plywood model, and then the segments are combined to present the overall modulus values in three-dimensions. The calculated trends compare well with the trends in microhardness values measured for circumferential lamellar bone. Microhardness values are, as yet, the only measurements available for direct comparison. Although the model is not directly applicable to osteonal bone, which is composed of many hollow cylinders of lamellar bone, the range of calculated modulus values and the trends observed for off-axis calculations, compare well with measured values. © 1998 Chapman & Hall  相似文献   
6.
When we take a picture through transparent glass the image we obtain is often a linear superposition of two images: the image of the scene beyond the glass plus the image of the scene reflected by the glass. Decomposing the single input image into two images is a massively ill-posed problem: in the absence of additional knowledge about the scene being viewed there are an infinite number of valid decompositions. In this paper we focus on an easier problem: user assisted separation in which the user interactively labels a small number of gradients as belonging to one of the layers. Even given labels on part of the gradients, the problem is still ill-posed and additional prior knowledge is needed. Following recent results on the statistics of natural images we use a sparsity prior over derivative filters. This sparsity prior is optimized using the terative reweighted least squares (IRLS) approach. Our results show that using a prior derived from the statistics of natural images gives a far superior performance compared to a Gaussian prior and it enables good separations from a modest number of labeled gradients.  相似文献   
7.
8.
Abstract

The article demonstrates that multiple solution tasks (MSTs) in the context of geometry can serve as a research instrument for evaluating geometry knowledge and creativity. Geometry knowledge is evaluated based on the correctness and connectedness of solutions, whereas creativity is evaluated based on a combination of fluency, flexibility, and originality of solutions. In this article, the MST research instrument is introduced in connection with the theoretical analysis of the research literature and then explained and analyzed using geometry students’ performance results on one MST. The analysis shows that the research instrument differentiates between students belonging to high- and regular-level instruction groups and sheds light on the interrelations between components of geometry knowledge and creativity.  相似文献   
9.
Building on qualitative data collected from three groups of professionals who assessed the green colour of a public transportation bus, this paper develops a model of the relationship between physical artifacts and emotions. The model suggests that artifacts need to be analysed according to three conceptually distinct aspects: instrumentality, aesthetics and symbolism. These three aspects are suggested to arouse emotion through different mechanisms: a hygiene, a sensory and an associative mechanism. The model opens an arena for extensive future research on the role and influence of physical artifacts in general and on emotions in particular.  相似文献   
10.
The grain boundary mobility of polycrystalline alumina (α‐Al2O3), and the effective grain boundary mobility of the basal (0001) plane as it grew into polycrystalline alumina, was determined for undoped alumina, alumina doped with 23 ppm MgO, and alumina doped with 13 ppm CaO at 1600°C. Doping with MgO at a level below the solubility limit decreased the grain‐boundary mobility from 2.7 × 10?15 to 1.5 × 10?15 m2/s, and doping with CaO at a level below the solubility limit increased the mobility to 3.5 × 10?15 m2/s. For the undoped samples at 1600°C, the activation energy for the average grain boundary mobility was 372 ± 39 kJ/mol. The mobility of the (0001) plane growing into alumina doped with MgO at a level below the solubility limit decreased to 1.1 × 10?15 m2/s compared with the mobility of the (0001) plane growing into undoped alumina (2.5 × 10?15 m2/s), and the mobility of the (0001) plane growing into alumina doped with CaO (below the solubility limit) increased to 3.2 × 10?15 m2/s. The activation energy for the mobility of the (0001) plane was 483 ± 76 kJ/mol. Although a measured Ca excess of 2.6 Ca/nm2 at the boundary between the (0001) plane and CaO‐doped alumina is correlated with an increased mobility, the platelike morphology of CaO‐doped polycrystalline alumina is associated with an increased mobility of nonbasal planes.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号