全文获取类型
收费全文 | 2980篇 |
免费 | 94篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 46篇 |
综合类 | 6篇 |
化学工业 | 1054篇 |
金属工艺 | 65篇 |
机械仪表 | 65篇 |
建筑科学 | 152篇 |
矿业工程 | 9篇 |
能源动力 | 56篇 |
轻工业 | 194篇 |
水利工程 | 9篇 |
石油天然气 | 3篇 |
无线电 | 203篇 |
一般工业技术 | 452篇 |
冶金工业 | 265篇 |
原子能技术 | 37篇 |
自动化技术 | 463篇 |
出版年
2023年 | 23篇 |
2022年 | 35篇 |
2021年 | 68篇 |
2020年 | 39篇 |
2019年 | 39篇 |
2018年 | 39篇 |
2017年 | 40篇 |
2016年 | 76篇 |
2015年 | 55篇 |
2014年 | 71篇 |
2013年 | 115篇 |
2012年 | 119篇 |
2011年 | 158篇 |
2010年 | 127篇 |
2009年 | 112篇 |
2008年 | 129篇 |
2007年 | 108篇 |
2006年 | 123篇 |
2005年 | 87篇 |
2004年 | 86篇 |
2003年 | 65篇 |
2002年 | 45篇 |
2001年 | 54篇 |
2000年 | 52篇 |
1999年 | 58篇 |
1998年 | 94篇 |
1997年 | 62篇 |
1996年 | 50篇 |
1995年 | 46篇 |
1994年 | 39篇 |
1993年 | 37篇 |
1992年 | 29篇 |
1991年 | 35篇 |
1990年 | 24篇 |
1989年 | 22篇 |
1987年 | 25篇 |
1985年 | 25篇 |
1983年 | 23篇 |
1980年 | 26篇 |
1978年 | 20篇 |
1977年 | 22篇 |
1976年 | 26篇 |
1975年 | 26篇 |
1974年 | 69篇 |
1973年 | 54篇 |
1972年 | 54篇 |
1971年 | 53篇 |
1970年 | 50篇 |
1969年 | 45篇 |
1968年 | 38篇 |
排序方式: 共有3079条查询结果,搜索用时 15 毫秒
61.
The selfdiffusion coefficients of acetone and benzene are studied in the systems acetone/poly(methylmethacrylate) and benzene/poly(methylmethacrylate) by means of the spin echo technique as function of concentration and temperature. From the dependence of temperature, the activation energies are calculated as function of concentration. The dependence of concentration of the selfdiffusion coefficients is discussed using the theory of Free Volume according to FUJITA. The Free Volume of the poly(methylmethacrylate) is calculated as function of temperature. 相似文献
62.
Compatible polymer blends of poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA) can be used as suitable model systems for investigating the relationship between the physico-chemical structure of polymers and their piezo- and pyroelectric activity. The structure of PVDF/PMMA blends can be varied over a very wide range which can lead to a strong influence on the piezo- and pyroelectric activity and the corresponding coefficients d31 and g3. The values of d31 and g3 were found to vary over nearly five decades whereas the normalized coefficients and remain largely unaffected. This emphasizes the importance of the molecular processes causing the macroscopic polarization P during the poling procedure. For a given polarization P and a given temperature T the properties of the polymer matrix, however, are far less important for the values obtained for d31 and g3. The experimental results were compared with theoretical predictions based on models which were recently developed by Tashiro et al., Broadhurst et al. and by Mopsik et al.. Considering the appropriate scope of each model a good agreement between theory and experiment is observed and general contradictions have not been found. 相似文献
63.
M. J. Albrink R. M. Krauss F. T. Lindgren J. Von Der Groeben S. Pan P. D. Wood 《Lipids》1980,15(9):668-676
The interrelationships among fatness measures, plasma triglycerides and high density lipoproteins (HDL) were examined in 131
normal adult subjects: 38 men aged 27–46, 40 men aged 47–66, 29 women aged 27–46 and 24 women aged 47–66. None of the women
were taking estrogens or oral contraceptive medication. The HDL concentration was subdivided into HDL2b, HDL2a and HDL3 by a computerized fitting of the total schlieren pattern to reference schlieren patterns. Anthropometric measures employed
included skinfolds at 3 sites, 2 weight/height indices and 2 girth measurements. A high correlation was found among the various
fatness measures. These measures were negatively correlated with total HDL, reflecting the negative correlation between fatness
measures and HDL2 (as the sum of HDL2a and2b). Fatness measures showed no relationship to HDL3. There was also an inverse correlation between triglyceride concentration and HDL2. No particular fatness measure was better than any other for demonstrating the inverse correlation with HDL but multiple
correlations using all of the measures of obesity improved the correlations. Partial correlations controlling for fatness
did not reduce any of the significant correlations between triglycerides and HDL2 to insignificance. The weak correlation between fatness and triglycerides was reduced to insignificance when controlled for
HDL2.
Presented (in part) at the Annual Meeting of the Oil Chemists' Society in St. Louis, MO, May 1978. 相似文献
64.
Finkbeiner Bernd Mariani Leonardo 《International Journal on Software Tools for Technology Transfer (STTT)》2021,23(4):545-546
International Journal on Software Tools for Technology Transfer - 相似文献
65.
Automatic classification of defects on the product surface in grinding and polishing 总被引:4,自引:0,他引:4
Xiang Zhang Carsten Krewet Bernd Kuhlenktter 《International Journal of Machine Tools and Manufacture》2006,46(1):59-69
Grinding and polishing are standard operations in material processing. It is important to inspect and classify the potential defects existing on the product surfaces after grinding and polishing in order to obtain high quality in both functionality and aesthetics. Post-processing handling can be carried out after the defects have been correctly classified. A vision system already exists to detect and classify defects based on captured grayscale images automatically. The system is able to find and locate the defects precisely, but is incapable of placing those defects into the right predefined classes. The old system classifies the defects 30% of the time into the 15 predefined classes based on shape features. In this paper, a new classification strategy has been introduced using diverse extracted features. In addition to shape features, some other feature extraction methods were tried, e.g. Laws filter bank, DCT (Discrete Cosine Transformation) filter bank, Gabor filter bank, and statistical features based on co-occurrence matrix. The Support Vector Machine (SVM) was used as a multi-class classifier with input of the extracted features. By combining the Gabor filter features and the statistical features, the classification rate of the system can reach 82% overall right rate, which is applicable practically. 相似文献
66.
本文介绍了民主德国关于堆焊工艺的一些最新研究成果以及为提高焊接自动化程度对设备的研究和发展。哈雷中央焊接研究所研制的堆焊-裁荷-填充材料-工艺系统(“A—B—Z—V”),作为选择工艺及填充材料的依据,从构件分析出发,生产了用于旋转件的特种程序的机器人ZIS12—63.孔堆焊设备ZIS12—96,轨道堆焊机ZIS13—43,轻便堆焊机ZIS15—40.以及用于侧板堆焊的机器人和煤球模型堆焊机器人。 相似文献
67.
An efficient method for solving the Signorini problem in the simulation of free-form surfaces produced by belt grinding 总被引:1,自引:3,他引:1
Xiang Zhang Bernd Kuhlenktter Klaus Kneupner 《International Journal of Machine Tools and Manufacture》2005,45(6):641-648
Industrial robots are recently introduced to the belt grinding of free-form surfaces to obtain high productive efficiency and constant surface quality. The simulation of belt grinding process can facilitate planning grinding paths and writing robotic programs before manufacturing. In simulation, it is crucial to get the force distribution in the contact area between the workpiece and the elastic contact wheel because the uneven distributed local forces are the main reason to the unequal local removals on the grated surface. The traditional way is to simplify this contact problem as a Signorini contact problem and use the finite element method (FEM) to calculate the force distribution. However, the FEM model is too computationally expensive to meet the real-time requirement. A new model based on support vector regression (SVR) technique is developed in this paper to calculate the force distribution instead of the FEM model. The new model approximates the FEM model with an error smaller than 5%, but executes much faster (1 s vs 15 min by FEM). With this new model, the real-time simulation and even the on-line robot control of grinding processes can be further conducted. 相似文献
68.
69.
70.
Zilu Liang Bernd Ploderer Wanyu Liu Yukiko Nagata James Bailey Lars Kulik Yuxuan Li 《Personal and Ubiquitous Computing》2016,20(6):985-1000
Getting enough quality sleep is a key part of a healthy lifestyle. Many people are tracking their sleep through mobile and wearable technology, together with contextual information that may influence sleep quality, like exercise, diet, and stress. However, there is limited support to help people make sense of this wealth of data, i.e., to explore the relationship between sleep data and contextual data. We strive to bridge this gap between sleep-tracking and sense-making through the design of SleepExplorer, a web-based tool that helps individuals understand sleep quality through multi-dimensional sleep structure and explore correlations between sleep data and contextual information. Based on a two-week field study with 12 participants, this paper offers a rich understanding on how technology can support sense-making on personal sleep data: SleepExplorer organizes a flux of sleep data into sleep structure, guides sleep-tracking activities, highlights connections between sleep and contributing factors, and supports individuals in taking actions. We discuss challenges and opportunities to inform the work of researchers and designers creating data-driven health and well-being applications. 相似文献