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   165篇
  免费   6篇
化学工业   43篇
机械仪表   1篇
建筑科学   8篇
能源动力   2篇
轻工业   18篇
无线电   25篇
一般工业技术   18篇
冶金工业   29篇
自动化技术   27篇
  2023年   6篇
  2022年   8篇
  2021年   13篇
  2020年   2篇
  2019年   5篇
  2018年   3篇
  2017年   2篇
  2016年   2篇
  2015年   4篇
  2014年   7篇
  2013年   3篇
  2012年   4篇
  2011年   9篇
  2010年   2篇
  2009年   3篇
  2008年   4篇
  2007年   2篇
  2006年   7篇
  2005年   5篇
  2004年   1篇
  2003年   4篇
  2002年   6篇
  2001年   5篇
  2000年   5篇
  1999年   3篇
  1998年   15篇
  1997年   8篇
  1996年   10篇
  1995年   5篇
  1994年   4篇
  1993年   1篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1983年   1篇
  1982年   3篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
排序方式: 共有171条查询结果,搜索用时 14 毫秒
71.
72.
A CH3OH FIR system has been developed for plasma diagnostics. A CO2 laser devoted to pump the CH3OH molecule has been studied. Different internal diameters of FIR cavity, input coupling holes and focusing lenses have been experimented. It has been found that the system formed by three subsystems-pump laser, guiding channel and FIR cavity-behaves like an unique system. A long term stability has been reached with a proper system design.  相似文献   
73.
A new boundary integral formulation for the aerodynamic analysis of an aircraft (in particular, a tiltrotor) in arbitrary motion is presented. The formulation is based on the velocity potential for compressible flows, and as such is an extension of past work of the authors. The distinguishing feature is that the boundary integral representation is written for a surface in arbitrary motion with respect to a frame of reference which in turn moves in arbitrary motion with respect to the undisturbed air. Thus, the integrals are evaluated on the emission surface, which is the locus of the emitting points at the locations (in the moving frame) that they had when the signal influencing a given point at a given time was emitted. The differences with respect to related formulations (e.g., Ffowcs Williams and Hawkings) are outlined. Also, the advantages of the present formulation with respect to the preceding ones by the authors are discussed. Numerical validation results are presented for the limited case of helicopter rotors in hover.  相似文献   
74.
The article introduces a new fast convolution-type technique for computing the multidimensional periodic convolutions of signals defined on generic lattices. The method presented does not evaluate multidimensional periodic convolutions via multidimensional FFTs but with an original algorithm. The major advantages of this technique are that it is more efficient than the well-known FFT-based fast convolution method and that its efficiency increases with the signal's dimensionality. One striking indication of its computational efficiency is that the number of operations per output point required by this method with nonseparable kernels of assigned dimensions is always smaller than the number of operations required by classical fast convolution algorithms with separable kernels of identical dimensions  相似文献   
75.
76.
Directional Discretized Occluders for Accelerated Occlusion Culling   总被引:1,自引:0,他引:1  
We present a technique for accelerating the rendering of high depth-complexity scenes. In a preprocessing stage, we approximate the input model with a hierarchical data structure and compute simple view-dependent polygonal occluders to replace the complex input geometry in subsequent visibility queries. When the user is inspecting and visualizing the input model, the computed occluders are used to avoid rendering geometry which cannot be seen. Our method has several advantages which allow it to perform conservative visibility queries efficiently and it does not require any special graphics hardware. The preprocessing step of our approach can also be used within the framework of other visibility culling methods which need to pre-select or pre-render occluders. In this paper, we describe our technique and its implementation in detail, and provide experimental evidence of its performance. In addition, we briefly discuss possible extensions of our algorithm.  相似文献   
77.
Dilated cardiomyopathy (DCM) is the leading indication for heart transplantation. TTN gene truncating mutations account for about 25% of familial DCM cases and for 18% of sporadic DCM cases. The clinical relevance of specific variants in TTN has been difficult to determine because of the sheer size of the protein for which TTN encodes, as well as existing extensive genetic variation. Clinicians should communicate novel clinically-relevant variants and genotype–phenotype associations, so that animal studies evaluating the molecular mechanisms are always conducted with a focus on clinical significance. In the present study, we report for the first time the novel truncating heterozygous variant NM_001256850.1:c.72777_72783del (p.Phe24259Leufs*51) in the TTN gene and its association with DCM in a family with sudden death. This variant occurs in the A-band region of the sarcomere, in a known mutational hotspot of the gene. Truncating titin variants that occur in this region are the most common cause of DCM and have been rarely reported in asymptomatic individuals, differently from other pathogenic TTN gene variants. Further studies are warranted to better understand this particular clinically-relevant variant.  相似文献   
78.
Two physical processes are used for the removal of oil from oilseeds, one called “solution extraction” and the other “diffusion extraction.” In batch type solvent extraction plants, a diffusion process takes place. Due to their high steam and labor requirements, such plants are being steadily replaced with continuous solvent extraction plants, whose main component is the extractor which can be either of the immersion or percolation type. The combined use of these two types of extractor makes it possible to extract oil directly from oilseeds, even if they have a high oil content, with no need for continuous screw presses or expellers. Comparative data on the processes in most common use are given.  相似文献   
79.
In view of the fact that a considerable proportion of the population particularly at risk (the aged, children, the sick, etc.) spend many hours of the day indoors, the authors report the results of an investigation carried out on the building characteristics of 1833 houses sampled in four towns in the Marches region. The questionnaire of Fusillo et al. was used. The results show an excellent situation with regard both to the quality of outdoor air and acoustic pollution (only 27% of the sample complained of the vicinity of their house to zones of intense traffic). The low index of overcrowding (0.7 inhabitants per room) as well as the overall surface area of the houses (in 60% more than 100 m2), the large number of bathrooms (almost 50% of the houses with two, and another 15% with three or more), and the prevalence of detached houses are factors that show how the Marchean population pay particular attention to building criteria. However, even though from the structural standpoint the housing situation might seem a very good one, specific problems can be found, also common to other Italian regions, regarding building techniques and the materials adopted (e.g. the use of reinforced concrete, which together with the undoubted advantages it offers also has a number of disadvantages). The authors therefore stress the need for incentivating a bioecologically based building tradition, even if this is economically more costly, and give guidelines on how to conciliate the bioecological and economic aspects with regard to choice and use of materials. Finally, they express the hope that the "EC" symbol foreseen for building materials by Law No. 246 of 21 April 1993 will be adequately used in the ways laid down in appendix A to that law.  相似文献   
80.
Alkaptonuria (AKU) is a rare multisystem metabolic disease caused by deficient activity of homogentisate 1,2‐dioxygenase (HGD), which leads to the accumulation of homogentisic acid (HGA). Currently, there is no treatment for AKU. The sole drug with some beneficial effects is the herbicide nitisinone ( 1 ), an inhibitor of p‐hydroxyphenylpyruvate dioxygenase (4‐HPPD). 1 has been used as a life‐saving drug in infants with type I tyrosinemia despite severe side effects due to the buildup of tyrosine. Four clinical trials of nitisinone to treat AKU have shown that 1 consistently decreases HGA levels, but also caused the accumulation of tyrosine in blood serum. Moreover, the human preclinical toxicological data for 1 are incomplete. In this work, we performed pharmacodynamics and toxicological evaluations of 1 , providing the first report of LD50 values in human cells. Intracellular tyrosinemia was also evaluated. Three additional 4‐HPPD inhibitors with a more favorable profile than that of 1 in terms of IC50, LD50, and tyrosine accumulation were also identified among commercially available compounds. These may be promising starting points for the development of new therapeutic strategies for the treatment of AKU.  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