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   343篇
  免费   21篇
  国内免费   2篇
电工技术   1篇
化学工业   65篇
金属工艺   2篇
机械仪表   2篇
建筑科学   5篇
能源动力   9篇
轻工业   14篇
石油天然气   2篇
无线电   47篇
一般工业技术   73篇
冶金工业   14篇
原子能技术   10篇
自动化技术   122篇
  2022年   16篇
  2021年   11篇
  2020年   6篇
  2019年   6篇
  2018年   9篇
  2017年   13篇
  2016年   14篇
  2015年   13篇
  2014年   4篇
  2013年   13篇
  2012年   13篇
  2011年   31篇
  2010年   24篇
  2009年   18篇
  2008年   23篇
  2007年   18篇
  2006年   18篇
  2005年   9篇
  2004年   9篇
  2003年   6篇
  2002年   7篇
  2001年   2篇
  2000年   6篇
  1999年   3篇
  1998年   6篇
  1997年   6篇
  1996年   4篇
  1995年   5篇
  1994年   3篇
  1993年   3篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1989年   3篇
  1988年   2篇
  1987年   3篇
  1986年   4篇
  1985年   3篇
  1984年   3篇
  1983年   3篇
  1981年   3篇
  1979年   3篇
  1978年   2篇
  1976年   2篇
  1974年   1篇
  1972年   1篇
  1971年   1篇
  1970年   1篇
  1969年   3篇
  1968年   2篇
排序方式: 共有366条查询结果,搜索用时 15 毫秒
31.
Abstract— As the healthcare system changes and progresses, the need for different types of high‐performing displays is also evolving. There are three categories of displays: (a) embedded (as part of life saving devices), (b) informative (for patient data and history, and managing workflow), and (c) imaging (high performing for diagnosis). The challenges of AMLCDs, which are the display of choice at the moment mainly in digital imaging, will be discussed. These challenges include very high resolution, high brightness, and wide viewing angle. The current performance of AMLCDs and the areas which they need to improve will be reviewed. A brief summary of the standards used to specify medical (diagnostic) displays will follow. A look into the future will predict the role of displays in hospitals.  相似文献   
32.
33.
34.
We investigate the relations between two major properties of multiparty protocols: fault tolerance (or resilience ) and randomness . Fault-tolerance is measured in terms of the maximum number of colluding faulty parties, t , that a protocol can withstand and still maintain the privacy of the inputs and the correctness of the outputs (of the honest parties). Randomness is measured in terms of the total number of random bits needed by the parties in order to execute the protocol. Previously, the upper bound on the amount of randomness required by general constructions for securely computing any nontrivial function f was polynomial both in n , the total number of parties, and the circuit-size C(f) . This was the state of knowledge even for the special case t=1 (i.e., when there is at most one faulty party). In this paper we show that for any linear-size circuit, and for any number t < n/3 of faulty Received 30 April 1998 and revised 3 January 1999 and 1 July 1999  相似文献   
35.
Adi Maoz 《Water research》2010,44(3):981-4482
Pharmaceutical compounds and dissolved organic matter (DOM) are co-introduced into the environment by irrigation with reclaimed wastewater and/or application of biosolids. In this study, we evaluate the role and mechanism of interaction of the pharmaceuticals naproxen and carbamazepine with structural fractions of biosolids-derived DOM. Sorption interactions were estimated from dialysis-bag experiments at different pHs.Sorption of naproxen and carbamazepine by the hydrophobic acid fraction exhibited strong pH-dependence. With both pharmaceuticals, the highest sorption coefficients (KDOC) were at pH 4. With the hydrophobic neutral fraction, pH affected only naproxen sorption (decreasing with increasing pH). Among the hydrophilic DOM fractions, the hydrophilic acid fraction exhibited the highest KDOC value for carbamazepine, probably due to their bipolar character. In the hydrophilic acid fraction-naproxen system, significant anionic repulsion was observed with increasing pH. The hydrophilic base fraction contains positively charged functional groups. Therefore with increasing ionization of naproxen (with increasing pH), KDOC to this fraction increased. The hydrophilic neutral fraction exhibited the lowest KDOC with both studied pharmaceuticals.The KDOC value of carbamazepine with the bulk DOM sample was higher than the calculated KDOC value based on sorption by the individual isolated fractions. The opposite trend was observed with naproxen at pH 8: the calculated KDOC value was higher than the value obtained for the bulk DOM. These results demonstrate that DOM fractions interact with each other and do not act as separate sorption domains.  相似文献   
36.
A seawater inlet pipe failed in service. The visual examination showed that the backing bar was present inside the pipe and the failure was characterized by leaks at approximately 4–8 o’clock position near that backing bar. The finite element analysis of fluid in the seawater inlet pipe showed that the eddy zone was formed near the backing bar. The leaks and crater-like surfaces were noticed on the inner pipe surface at which the finite element analysis modeled the possibility of the formation of eddy zone.  相似文献   
37.
A systematic holistic mathematical programming (HMP) is proposed to formulate a mixed integer nonlinear programming (MINLP) model for one-step optimization of water-allocation and heat exchange network (WAHEN) designs with single- or multi-contaminant water streams. The proposed model formulation and solution strategy are believed to be superior to the available ones in the following aspects. First, a comprehensive representation combining two separate superstructures is adopted to capture the structural characteristics of the integrated WAHEN. Then, a hybrid optimization strategy integrating stochastic and deterministic components is developed for the resulting MINLP model and, also, an interactive iteration method is adopted based on sensitivity analysis to guide the search toward a potential global optimum. Finally, evolutionary strategies and manipulations are executed to enhance WAHEN configurations. Two illustrative examples are presented to demonstrate the validity and advantages of the proposed approach.  相似文献   
38.
A method is described for perceptually transparent data concealment and watermarking in audio. The proposed system replaces redundant and imperceptible frequency components with hidden data. A psychoacoustic model is used to identify suitable frequency locations for data hiding. Such a method is complicated by the windowing and overlapping requirements used for signal conditioning. The proposed system uses data flipping in place of windowing and incorporates a novel data detection scheme with adaptive weighting to increase the robustness of the watermark transmission. The resistance of the watermarking system to filtering, amplitude scaling and additive white noise is measured and results presented.  相似文献   
39.
The possibility of synthesizing light fields satisfying given requirements within a three-dimensional (3-D) space domain was proposed and demonstrated during recent years. In this paper we present fundamental physical properties characterizing 3-D fields and propose analytical and numerical procedures to synthesize them. These methods solve the proper wave equation under 3-D constraints. Since the manipulation of light is a basic task, this is an effective approach to deal with classical as well as novel problems in optics and photonics technologies. We discuss exciting new potential areas of application and extensions of this concept  相似文献   
40.
It is common to assume that structures are designed in view of 50 year life cycle as per Euro-Code 2 and other codes. In special cases, structures are designed in view of longer life cycle, such as bridges, important infrastructure facilities, important religious structures or in case of extended returning period of seismic event or floods. Beside issues of durability and maintenance aspects, this involves also the need to cover the probability of exceeding characteristic design live loads during the extended period, while keeping the same levels of the accepted risk that were assumed by the various codes, as good enough for the standard 50 year life cycle. Bearing in mind that design procedures, formulations, materials characteristic strengths and partial safety factors are used for these structures as per the existing codes, scaling of partial safety factors, or alternatively an additional "compensating" factor is required. A simplified approach and procedure to arrive at a reasonable calibration of the code safety factors based on 50 years to compensate for an extended life cycle, based upon structural reliability considerations, is proposed.  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