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   258篇
  免费   9篇
电工技术   13篇
化学工业   31篇
金属工艺   2篇
机械仪表   7篇
建筑科学   7篇
能源动力   11篇
轻工业   11篇
水利工程   1篇
无线电   40篇
一般工业技术   65篇
冶金工业   16篇
原子能技术   1篇
自动化技术   62篇
  2023年   4篇
  2022年   10篇
  2021年   6篇
  2020年   4篇
  2019年   3篇
  2018年   10篇
  2017年   11篇
  2016年   7篇
  2015年   4篇
  2014年   12篇
  2013年   15篇
  2012年   8篇
  2011年   9篇
  2010年   4篇
  2009年   9篇
  2008年   13篇
  2007年   11篇
  2006年   12篇
  2005年   9篇
  2004年   5篇
  2003年   4篇
  2002年   4篇
  2001年   6篇
  2000年   4篇
  1999年   7篇
  1998年   8篇
  1997年   6篇
  1996年   10篇
  1995年   4篇
  1994年   5篇
  1993年   2篇
  1992年   5篇
  1991年   4篇
  1990年   3篇
  1989年   3篇
  1988年   1篇
  1987年   1篇
  1985年   4篇
  1984年   1篇
  1983年   5篇
  1982年   1篇
  1981年   1篇
  1980年   3篇
  1978年   3篇
  1977年   3篇
  1976年   1篇
  1974年   1篇
  1970年   1篇
排序方式: 共有267条查询结果,搜索用时 46 毫秒
11.
This paper proposes hybrid classification models and preprocessing methods for enhancing the consonant-vowel (CV) recognition in the presence of background noise. Background Noise is one of the major degradation in real-time environments which strongly effects the performance of speech recognition system. In this work, combined temporal and spectral processing (TSP) methods are explored for preprocessing to improve CV recognition performance. Proposed CV recognition method is carried out in two levels to reduce the similarity among large number of CV classes. In the first level vowel category of CV unit will be recognized, and in the second level consonant category will be recognized. At each level complementary evidences from hybrid models consisting of support vector machine (SVM) and hidden Markov models (HMM) are combined for enhancing the recognition performance. Performance of the proposed CV recognition system is evaluated on Telugu broadcast database for white and vehicle noise. The proposed preprocessing methods and hybrid classification models have improved the recognition performance compared to existed methods.  相似文献   
12.
In Bacillus subtilis, CodW peptidase and CodX ATPase function together as a distinctive ATP-dependent protease called CodWX, which participates in protein degradation and regulates cell division. The molecular structure of CodX and the assembly structure of CodW-CodX have not yet been resolved. Here we present the first three-dimensional structure of CodX N-terminal (N) and C-terminal (C) domain including possible structure of intermediate (I) domain based on the crystal structure of homologous Escherichia coli HslU ATPase. Moreover, the biologically relevant CodWX (W(6)W(6)X(6)) octadecamer complex structure was constructed using the recently identified CodW-HslU hybrid crystal structure. Molecular dynamics (MD) simulation shows a reasonably stable structure of modeled CodWX and explicit behavior of key segments in CodX N and C domain: nucleotide binding residues, GYVG pore motif and CodW-CodX interface. Predicted structure of the possible I domain is flexible in nature with highly coiled hydrophobic region (M153-M206) that could favor substrate binding and entry. Electrostatic surface potential observation unveiled charge complementarity based CodW-CodX interaction pattern could be a possible native interaction pattern in the interface of CodWX. CodX GYVG pore motif structural features, flexible nature of glycine (G92 and G95) residues and aromatic ring conformation preserved Y93 indicated that it may follow the similar mode during the proteolysis mechanism as in the HslU closed state. This molecular modeling study uncovers the significance of CodX N and C domain in CodWX complex and provides possible explanations which would be helpful to understand the CodWX-dependent proteolysis mechanism of B. subtilis.  相似文献   
13.
This article is about testing the equality of several normal means when the variances are unknown and arbitrary, i.e., the set up of the one-way ANOVA. Even though several tests are available in the literature, none of them perform well in terms of Type I error probability under various sample size and parameter combinations. In fact, Type I errors can be highly inflated for some of the commonly used tests; a serious issue that appears to have been overlooked. We propose a parametric bootstrap (PB) approach and compare it with three existing location-scale invariant tests—the Welch test, the James test and the generalized F (GF) test. The Type I error rates and powers of the tests are evaluated using Monte Carlo simulation. Our studies show that the PB test is the best among the four tests with respect to Type I error rates. The PB test performs very satisfactorily even for small samples while the Welch test and the GF test exhibit poor Type I error properties when the sample sizes are small and/or the number of means to be compared is moderate to large. The James test performs better than the Welch test and the GF test. It is also noted that the same tests can be used to test the significance of the random effect variance component in a one-way random model under unequal error variances. Such models are widely used to analyze data from inter-laboratory studies. The methods are illustrated using some examples.  相似文献   
14.
15.
Fish protein hydrolysates from three freshwater carps, Catla catla, Labeo rohita and Cirrhinus mrigala with different degree of hydrolysis (DH) (5%, 10%, 15% and 20%), were prepared using Flavorzyme enzyme and designated as HCF, HRF and HMF, respectively. The angiotensin I‐converting enzyme (ACE) inhibitory activity of hydrolysates was found to vary from 43 ± 2% to 71 ± 3%. Based on ACE inhibitory activity, HRF with DH‐15% was taken up for further study. The mode of ACE activity inhibition by HRF‐DH 15% was mixed type as revealed by Lineweaver–Burk plot. Sequential digestion of HRF‐DH 15% using pepsin and pancreatin decreased the ACE inhibitory activity from 76% to 63%. Partial purification of HRF‐DH 15% by size exclusion chromatography gave three different fractions designated as F‐1, F‐2 and F‐3 with the molecular mass in the range of 6456–407 Da. Fraction 2 had significantly higher ACE inhibitory activity than the other fractions.  相似文献   
16.
Much of the world’s quantitative data reside in scattered web tables. For a meaningful role in Big Data analytics, the facts reported in these tables must be brought into a uniform framework. Based on a formalization of header-indexed tables, we proffer an algorithmic solution to end-to-end table processing for a large class of human-readable tables. The proposed algorithms transform header-indexed tables to a category table format that maps easily to a variety of industry-standard data stores for query processing. The algorithms segment table regions based on the unique indexing of the data region by header paths, classify table cells, and factor header category structures of two-dimensional as well as the less common multidimensional tables. Experimental evaluations substantiate the algorithmic approach to processing heterogeneous tables. As demonstrable results, the algorithms generate queryable relational database tables and semantic-web triple stores. Application of our algorithms to 400 web tables randomly selected from diverse sources shows that the algorithmic solution automates end-to-end table processing.  相似文献   
17.
The introduction of Computerized Numeric Control (CNC) technology in manufacturing industries revolutionized the production process a few decades back. There are some health and safety problems associated with these machine operations, however. The main objectives of the present work is to study the health and safety issues associated with the CNC machines with respect to control and display, specifically to determine the frequency, intensity of discomfort, and its interference in operating different CNC machines as reported by the workers operating them. The postural discomfort associated with CNC machines was studied, and the frequency, intensity of discomfort, and interference of the level of discomfort with the participants' ability to work were recorded and analyzed. The study revealed that 20.5% of the operators reported discomfort 1 or 2 times, 25.4% experienced discomfort 3 to 4 times in a week, 37.7% had discomfort daily, and 16.4% reported discomfort several times a day. Discomfort was reported in all the body parts involved (lower back, neck, upper back, shoulder, and leg), but the highest discomfort scores were associated with the shoulder and arm region. Workers reporting discomfort several times a day also reported high mean discomfort scores. The study established that the frequency and intensity of the discomfort in all body parts is related to the position of the control panel and display. © 2012 Wiley Periodicals, Inc.  相似文献   
18.
In this paper, a new multi stage vector quantization with energy clustered training set is proposed for color image coding. The input image is applied with orthogonal polynomials based transformation and the energy clustered transformed training vectors are obtained with reduced dimension. The stage-by-stage codebook for vector quantization is constructed from the proposed transformed training vectors so as to reduce computational complexity. This method also generates a single codebook for all the three color components, utilizing the inter-correlation property of individual color planes and interactions among the color planes due to the proposed transformation. As a result, the color image encoding time is only slightly higher than that of gray scale image coding time and in contrast to the existing color image coding techniques, whose time is thrice greater than that of gray scale image coding. The experimental results reveal that only 35 % and 10 % of transform coefficients are sufficient for smaller and larger blocks respectively, for the reconstruction of images with good quality. The proposed multi stage vector quantization technique is faster when compared to existing techniques and yields better trade-off between image quality and block size for encoding.  相似文献   
19.
A new weighted‐sum‐of‐gray gases (WSGG) model that is based on the statistical narrow band model (SNB) RADCAL is proposed for use in computational fluid dynamic (CFD) simulations of air and oxy‐combustion. When employed in conjunction with the discrete ordinates (DO) method, the model predictions compare well against line‐by‐line benchmark data that have been made available recently that are based on the latest spectroscopic databases. Furthermore, the model compares well against the EM2C SNB model calculations that have served as benchmark data in three‐dimensional geometries. Radiative transfer calculations in these prototypical problems therefore confirm recent experimental observations that SNB RADCAL and EM2C SNB serve as good model databases to develop approximate radiative property models. To achieve an optimum balance of speed and accuracy in computationally intensive CFD simulations, non‐gray formulations of the WSGG model are also employed with the P1 model and solutions are compared against those generated by the DO model. While the P1 model gave favorable comparisons when cold, black walls were present, the errors in the surface incident radiative flux predictions increased in the presence of hot, reflecting walls. Finally, in fully coupled simulations of natural gas combustion under air‐firing and oxy‐firing modes, the predicted incident radiative flux profiles were distinctly different between the gray and non‐gray calculations at regions of high temperature gradients, while the centerline temperature predictions were comparatively unaffected. The effects of turbulence radiation interactions were also accounted for through the temperature self‐correlation term. However, the magnitudes of the temperature fluctuations were small and localized within this furnace and did not significantly alter our predictions. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
20.
Journal of Mechanical Science and Technology - Self-healing materials heal partially or completely when damage occurs to restore the functionality of the material. Self-healing technology has found...  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