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   512篇
  免费   25篇
电工技术   4篇
综合类   2篇
化学工业   138篇
金属工艺   10篇
机械仪表   12篇
建筑科学   25篇
矿业工程   1篇
能源动力   33篇
轻工业   81篇
水利工程   4篇
石油天然气   1篇
无线电   26篇
一般工业技术   98篇
冶金工业   17篇
原子能技术   7篇
自动化技术   78篇
  2024年   3篇
  2023年   4篇
  2022年   15篇
  2021年   15篇
  2020年   12篇
  2019年   22篇
  2018年   30篇
  2017年   21篇
  2016年   22篇
  2015年   11篇
  2014年   14篇
  2013年   61篇
  2012年   44篇
  2011年   46篇
  2010年   35篇
  2009年   36篇
  2008年   40篇
  2007年   25篇
  2006年   24篇
  2005年   10篇
  2004年   8篇
  2003年   9篇
  2002年   5篇
  2001年   3篇
  2000年   2篇
  1999年   3篇
  1998年   5篇
  1997年   4篇
  1996年   1篇
  1994年   2篇
  1993年   4篇
  1992年   1篇
排序方式: 共有537条查询结果,搜索用时 15 毫秒
61.
We successfully measured longitudinal strains in two full-scale steel pipe specimens subjected to loading combinations of internal pressure, axial tensile force and bending moments undergoing local buckling under controlled laboratory conditions. Carbon-coated fibers, for the first time, and standard communication fibers were used. By using the broadening factor of the Brillouin spectrum width, we can successfully predict the location and progression sequence of buckling patterns, prior their visual detection in the laboratory. The broadening factor processing time is more efficient than multiple-peak fitting of the Brillouin spectrum method. Thus, it is capable of proving real-time deformation progression in structural health monitoring applications. High strength carbon-coated fibers are found to be superior to standard communication fibers in two respects: they provide more accurate readings and are able to measure significantly larger strains.  相似文献   
62.

In this study, the pre-buckling and post-buckling behaviors of layered composite plates which were made of woven carbon fiber fabric with a circular hole in the middle were investigated experimentally and numerically. Firstly, load-displacement graphs of composite plates with different hole diameters were experimentally obtained under compressive load. Then the numerical load-displacement graphs of the plates were found with the ANSYS package program which used the finite element method. As a result, after linear buckling experimental and numerical results were found to be compatible with each other. In addition, damage behavior of plates after buckling with the aid of Tsai-Wu damage criterion was obtained similar to experimental results. The increase in hole diameter did not change the load-displacement behavior characteristics of the plates after buckling. However, it has reduced maximum damage load and maximum failure displacement. The stress at the perimeter of the hole increased significantly with the increase of the vertical displacement with immediately after the buckling but later was not significantly affected by this increase.

  相似文献   
63.

Technological advances in robotics increase progressively. Elder care is one of the work areas which have potential to involve robotic workforce. So, it is important to focus on interaction between humans and potential robot workers to prepare the organization for possible challenges. The current study examined the relationships between trust in robots and anthropomorphism of robots, intention to work with robots and preference of automation levels. For this purpose, 102 caregivers who work for elder care in a nursing home (aged between 19 and 40) participated in an experimental study. According to the results, anthropomorphism of robots did not make any difference in terms of trust in them. Trust in robots was significantly related to intention to work and preference of automation levels. Organizations may consider employees’ trust in robots as an important factor before adapting them to workplace area.

  相似文献   
64.
Potential modulated attenuated total reflectance (PM-ATR) spectroscopy has been employed to study charge transfer processes in Prussian blue (PB) films deposited on indium tin oxide (ITO) electrodes. PM-ATR is a planar waveguide-based spectroelectrochemical technique in which the optical response of an electroactive film is measured as a function of applied potential and modulation frequency. The multiple internal reflection geometry of PM-ATR provides a significant sensitivity advantage over the single external reflectance geometry that has been employed in most prior electroreflectance studies. The apparent electron transfer rate of PB on ITO obtained using PM-ATR was compared to that obtained with conventional cyclic voltammetry; the respective rates, 0.33 ± 0.15 s−1 (n = 3) and 0.71 ± 0.37 s−1 (n = 10), are in good agreement.  相似文献   
65.
66.
Removal of copper ions from aqueous solutions by kaolinite and batch design   总被引:2,自引:0,他引:2  
The removal of copper ions from aqueous solutions by kaolinite was investigated by using a batch-type method. Effects of factors such as pH, ionic strength, temperature, acid-activation and calcination on copper adsorption were investigated. The uptake of copper was determined from changes in concentration as measured by atomic absorption spectrometry. The extent of copper adsorption increased with increasing pH and temperature and with decreasing ionic strength, acid-activation and calcination temperature. The Langmuir and Freundlich adsorption models were used to determine the isotherm parameters associated with the adsorption process. The results provide support for the adsorption of copper ions onto kaolinite. Thermodynamic parameters indicated the endothermic nature of copper adsorption on kaolinite. The experimental results were applied a batch design. As a result, the kaolinite may be used for removal of copper ions from aqueous solutions.  相似文献   
67.
Removal of copper ions from aqueous solutions by hazelnut shell   总被引:1,自引:0,他引:1  
There is a great potential of woody hazelnut shell to use in some applications. Sorption studies are one of these. For this reason in this paper, batch adsorption of Cu(2+) ions onto hazelnut shells was studied. The capacity of the adsorption for the removal of copper ions from aqueous solution was investigated under different conditions such as solution contact time (1-360 min), particle size (0-75, 75-150 and 150-200 microm), temperature of solution (25-60 degrees ) and solution pH (3-7). Moreover, zeta potential of particles at different initial pHs (2-10) was measured. The equilibrium data were processed according to Langmuir and Freundlich's models and higher adsorption capacity values towards Cu(2+) ions were shown. The adsorption kinetics was investigated and the best fit was achieved by a second-order equation.  相似文献   
68.
Interleukin-10 (IL-10) predominantly acts as an anti-inflammatory factor. Polymorphisms in the IL-10 gene promoter determine quantitative cytokine production. Doppler echocardiography and tissue Doppler imaging (TDI) are superior to conventional echocardiography to evaluate diastolic dysfunction. The IL-10 gene promoter polymorphism at position (-1082) was studied for its association with conventional and Doppler echocardiographic and TDI parameters in 112 hemodialysis (HD) patients. Blood pressure, serum C-reactive protein (CRP), and albumin levels were also examined for the association study. The genetic association study showed that among the HD patients, there was no difference in the prevalence of systolic and diastolic dysfunction between genotypes on conventional echocardiography. However, using Doppler echocardiography and TDI, high producers for the IL-10 -1082 promoter (-1082/GG) have higher E velocities, E/A values, lateral, and septal E' velocities and a lower isovolumic ventricular relaxation time than low (-1082/AA) and intermediate producers (-1082/GA). Significantly higher levels of serum CRP levels and lower plasma albumin levels were found in low and intermediate producers for the IL-10 -1082 promoter than high producers. The IL-10 genotype may balance the effects of inflammatory cytokines on the myocardium and may be a determinant of LV function in HD patients.  相似文献   
69.
The aim of this study was to compare the anatomical and functional characteristics of the lingual papilla among the Camelidae. For this purpose, tongues of alpaca, guanaco, and llama were used. Numerous long and thin filiform papillae were located in the median groove and none were detected on the rest of the dorsal surface of the lingual apex in alpaca. Secondary papillae originated from the base of some filiform papillae on the ventral surface of alpaca tongue. The bases of some filiform papillae of the lateral surface of the lingual apex were inserted into conspicuous grooves in guanaco and tips of filiform papillae on the dorsal surface of the lingual body were ended by bifurcated apex. On the dorsal surface of the lingual apex of llama, there were no filiform papillae but there were numerous filiform papillae on both the lateral margins of the ventral surface of the lingual apex. Fungiform papillae were distributed randomly on dorsal lingual surface and ventral margins of the tongues of all camelid species. Lenticular papillae were located on the lingual torus and varied in size and topographical distribution for each species. Circumvallate papillae had irregular surfaces in llama and alpaca, and smooth surface in guanaco. In conclusion, llama and alpaca tongues were more similar to each other, and tongues of all camelid species displayed more similarities to those of Bactrian and dromedary camels in comparison with other herbivores and ruminants. Microsc. Res. Tech. 79:61–71, 2016. © 2015 Wiley Periodicals, Inc.  相似文献   
70.
A hierarchical approach for fast bi‐dimensional empirical mode decomposition (B‐EMD) is proposed. The presented approach utilizes an efficient window size determination scheme that enables the multi‐level computation of the order statistics filter (OSF). Our detailed experiments show that the proposed OSF computation approach allows a significantly faster computation of an EMD without degrading the decomposition accuracy.  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