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   1356篇
  免费   51篇
  国内免费   4篇
电工技术   8篇
综合类   5篇
化学工业   372篇
金属工艺   52篇
机械仪表   21篇
建筑科学   76篇
矿业工程   6篇
能源动力   49篇
轻工业   157篇
水利工程   13篇
无线电   75篇
一般工业技术   245篇
冶金工业   116篇
原子能技术   16篇
自动化技术   200篇
  2023年   10篇
  2022年   16篇
  2021年   22篇
  2020年   10篇
  2019年   17篇
  2018年   18篇
  2017年   23篇
  2016年   30篇
  2015年   37篇
  2014年   39篇
  2013年   47篇
  2012年   78篇
  2011年   85篇
  2010年   68篇
  2009年   64篇
  2008年   78篇
  2007年   74篇
  2006年   46篇
  2005年   43篇
  2004年   40篇
  2003年   30篇
  2002年   34篇
  2001年   20篇
  2000年   32篇
  1999年   23篇
  1998年   25篇
  1997年   37篇
  1996年   10篇
  1995年   23篇
  1994年   20篇
  1993年   21篇
  1992年   13篇
  1991年   15篇
  1990年   20篇
  1989年   19篇
  1988年   20篇
  1987年   8篇
  1986年   9篇
  1985年   14篇
  1984年   18篇
  1983年   21篇
  1982年   10篇
  1981年   14篇
  1980年   19篇
  1979年   12篇
  1978年   16篇
  1977年   11篇
  1975年   8篇
  1973年   9篇
  1971年   8篇
排序方式: 共有1411条查询结果,搜索用时 15 毫秒
71.
The activity of ceramic honeycombs with varying material composition and degree of utilization is compared on a suitable model gas in a test plant. The tested honeycombs are standard products that have not been surface‐treated in any way. A propane‐air mixture was fed to the test plant and then oxidized in a high‐temperature furnace. The analysis of the conversion rate over the reaction temperature showed remarkable differences in activity. The honeycomb with the most promising results was further investigated with the exhaust gas from the drying process of a waste treatment plant. Finally, the activity of this honeycomb was assessed in a large‐scale trial in an existing running regenerative thermal oxidizer.  相似文献   
72.
73.
Synchronous programming is available through several formally defined languages having very different characteristics: Esterel is imperative, while Lustre and Signal are declarative in style; Statecharts and Argos are graphical languages that allow one to program by constructing hierarchical automata. Our motivation for taking the synchronous design paradigm further, integrating imperative, declarative (or dataflow), and graphical programming styles, is that real systems typically have components that match each of these profiles. This paper motivates our interest in the mixed language programming of embedded software around a number of examples, and sketches the semantical foundation of the Synchronie toolset which ensures a coherent computational model. This toolset supports a design trajectory that incorporates rapid prototyping and systematic testing for early design validation, an object oriented development methodology for long term software management, and formal verification at the level of automatically generated object code.  相似文献   
74.
To assist wayfinding and navigation, the display of maps and driving directions on mobile devices is nowadays commonplace. While existing system can naturally exploit GPS information to facilitate orientation, the inherently limited screen space is often perceived as a drawback compared to traditional street maps as it constrains the perception of contextual information. Moreover, occlusion issues add to this problem if the environment is shown from the popular egocentric perspective. In this paper we describe an interactive visualization system that addresses these problems by reallocating the available screen space. At the heart of our system are three novel visualization techniques: First, we propose a non‐standard perspective that allows to blend between the familiar pedestrian perspective and a standard map depiction with reduced occlusion. Second, we derive an efficient deformation technique that allows an interactive allocation of screen space to areas of interest like e.g. nearby touristic attractions. Finally, a path adaptive isometric perspective is proposed that reveals otherwise hidden facades in top‐down views. We describe efficient implementations of all techniques and exemplify our interactive system on real world urban models.  相似文献   
75.
Electronic Markets - Physical inactivity is a global public health problem that poses health risks to individuals and imposes financial burdens on already strained healthcare systems. Wearables...  相似文献   
76.
    
Zusammenfassung Dreißig Phenole wurden durch Destillation-Extraktion aus Röstkaffee isoliert, adsorptionschromatographisch von anderen Aromastoffen getrennt, durch GC-MS charakterisiert und grö-ßenordnungsmäßig bestimmt.Robusta-Kaffee enthielt die größten Mengen an Phenolen gefolgt vom neuen HybridArabusta (Côte d'Ivoire) andArabica. Neben der Sorte beeinflussen auch die Röstbedingungen Anzahl und Menge phenolischer Verbindungen.
Phenols in roasted coffees of different varieties. I.
Summary Thirty phenols were isolated from roasted coffee by distillation-extraction, separated from other constituents by adsorption-chromatography, and characterized by means of GC-MS.Robusta coffee contained the largest amount of phenols, followed byArabusta (Côte d'Ivoire) andArabica. Quantity and type of phenols depends on variety as well as on the roasting conditions.
  相似文献   
77.
Recent works in image editing are opening up new possibilities to manipulate and enhance input images. Within this context, we leverage well-known characteristics of human perception along with a simple depth approximation algorithm to generate non-photorealistic renditions that would be difficult to achieve with existing methods. Once a perceptually plausible depth map is obtained from the input image, we show how simple algorithms yield powerful new depictions of such an image. Additionally, we show how artistic manipulation of depth maps can be used to create novel non-photorealistic versions, for which we provide the user with an intuitive interface. Our real-time implementation on graphics hardware allows the user to efficiently explore artistic possibilities for each image. We show results produced with six different styles proving the versatility of our approach, and validate our assumptions and simplifications by means of a user study.  相似文献   
78.
Thethermodynamic state function free energy F(T,V,N) as function of the cluster distribution N and the thermodynamic parameters (temperature T and volume V) is calculated in the canonical ensemble. With the help of the Legendre transformation we get all other state functions for different boundary conditions. Monte Carlo simulations with 15000 particles starting from metastable homogeneous initial conditions are made for water and methanol. The Bethe-Weizsäcker ansatz and the Padé approximation are used for the binding energy of clusters. A first-order phase transition is observed under appropriate conditions.  相似文献   
79.
A comparative evaluation of length estimators of digital curves   总被引:2,自引:0,他引:2  
This paper compares previously published length estimators in image analysis having digitized curves as input. The evaluation uses multigrid convergence (theoretical results and measured speed of convergence) and further measures as criteria. This paper also suggests a new gradient-based method for length estimation, and combines a previously proposed length estimator for straight segments with a polygonalization method.  相似文献   
80.
IT infrastructure, such as servers and networking equipment, accounts for a large proportion of the IT costs in modern organizations. Typically, this IT infrastructure is shared among multiple applications and customers. Cost allocation of shared IT infrastructure is difficult and regularly based on biased cost allocation keys, which often causes free-rider problems. Measuring usage is technically difficult and incurs high costs. In this paper we propose a method to derive adequate estimators for the resource consumption of a customer-oriented service. These so-called resource profiles can then provide a basis for cost allocation keys. The estimators are derived from a series of load tests, as they are typically done before an application is launched in larger organizations. Such profiles need to be unbiased and precise even in cases of varying workloads and in rather heterogeneous environments. We describe the results of a set of experiments in an infrastructure provided by the BMW Group, and illustrate how the estimation can be integrated into existing IT service management processes. In our experiments we use Queuing Networks to validate the estimated resource profiles under different workloads.  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