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   1519篇
  免费   76篇
  国内免费   3篇
电工技术   34篇
综合类   5篇
化学工业   417篇
金属工艺   12篇
机械仪表   61篇
建筑科学   64篇
矿业工程   1篇
能源动力   86篇
轻工业   98篇
水利工程   5篇
石油天然气   2篇
无线电   145篇
一般工业技术   268篇
冶金工业   79篇
原子能技术   31篇
自动化技术   290篇
  2023年   15篇
  2022年   50篇
  2021年   72篇
  2020年   30篇
  2019年   31篇
  2018年   50篇
  2017年   42篇
  2016年   50篇
  2015年   35篇
  2014年   64篇
  2013年   112篇
  2012年   112篇
  2011年   121篇
  2010年   92篇
  2009年   94篇
  2008年   67篇
  2007年   71篇
  2006年   69篇
  2005年   35篇
  2004年   48篇
  2003年   32篇
  2002年   39篇
  2001年   22篇
  2000年   18篇
  1999年   24篇
  1998年   22篇
  1997年   22篇
  1996年   29篇
  1995年   21篇
  1994年   11篇
  1993年   19篇
  1992年   8篇
  1991年   5篇
  1990年   4篇
  1989年   7篇
  1988年   4篇
  1987年   4篇
  1986年   3篇
  1985年   3篇
  1983年   3篇
  1982年   4篇
  1981年   3篇
  1980年   6篇
  1979年   4篇
  1977年   3篇
  1976年   2篇
  1975年   3篇
  1973年   2篇
  1968年   3篇
  1966年   2篇
排序方式: 共有1598条查询结果,搜索用时 15 毫秒
61.
The foreseen uptake of hydrogen mobility is a fundamental step towards the decarbonization of the transport sector. Under such premises, both refueling infrastructure and vehicles should be deployed together with improved refueling protocols. Several studies focus on refueling the light-duty vehicles with 10 kgH2 up to 700 bar, however less known effort is reported for refueling heavy-duty vehicles with 30–40 kgH2 at 350 bar. The present study illustrates the application of a lumped model to a fuel cell bus tank-to-tank refueling event, tailored upon the real data acquired in the 3Emotion Project. The evolution of the main refueling quantities, such as pressure, temperature, and mass flow, are predicted dynamically throughout the refueling process, as a function of the operating parameters, within the safety limits imposed by SAE J2601/2 technical standard. The results show to refuel the vehicle tank from half to full capacity with an Average Pressure Ramp Rate (APRR) equal to 0.03 MPa/s are needed about 10 min. Furthermore, it is found that the effect of varying the initial vehicle tank pressure is more significant than changing the ambient temperature on the refueling performances. In conclusion, the analysis of the effect of different APRR, from 0.03 to 0.1 MPa/s, indicate that is possible to safely reduce the duration of half-to-full refueling by 62% increasing the APRR value from 0.03 to 0.08 MPa/s.  相似文献   
62.
Industrial energy efficiency represents a priority for European industrial competitiveness. Many studies offer contributions providing evidence of the existence of driving forces supporting the adoption of energy efficiency measures, but a structured approach to drivers for industrial energy efficiency is still lacking. Therefore, in the present study, we propose a definition of drivers, making emphasis on the industrial decision-maker perspective, that is needed for their classification here proposed. Focus is given to point out the difference between internal and external drivers, highlighting the major stakeholders responsible for their promotion. Drivers are further categorized into: regulatory, economic, informative, and vocational training. Moreover, we propose a framework describing the effect of drivers on barriers in the decision-making process, as well as a preliminary identification of the major stakeholders to promote drivers. The study opens several opportunities for further research in the area of industrial energy efficiency.  相似文献   
63.
We present fieldwork findings from the deployment of an interactive sensing system that supports the work of energy advisors who give face-to-face advice to low-income households in the UK. We focus on how the system and the data it produced are articulated in the interactions between professional energy advisors and their clients, and how they collaboratively anticipate, rehearse, and perform data work. In addition to documenting how the system was appropriated in advisory work, we elaborate the ‘overhead cost’ of building collaborative action into connected devices and sensing systems, and the commensurate need to support discrete workflows and accountability systems to enable the methodical incorporation of the IoT into collaborative action. We contribute an elaboration of the social, collaborative methods of data work relevant to those who seek to design and study collaborative IoT systems.  相似文献   
64.
65.
66.
Computational Visual Media - We present a novel approach to automatically recover, from a small set of partially overlapping spherical images, an indoor structure representation in terms of a 3D...  相似文献   
67.
68.
Objective

There is a pressing need to assess user-dependent reproducibility of multi-fibre probabilistic tractography in order to encourage clinical implementation of these advanced and relevant approaches. The goal of this study was to evaluate both intrinsic and inter-user reproducibility of corticospinal tract estimation.

Materials and methods

Six clinical datasets including motor functional and diffusion MRI were used. Three users performed an independent tractography analysis following identical instructions. Dice indices were calculated to quantify the reproducibility of seed region, fMRI-based end region, and streamline maps.

Results

The inter-user reproducibility ranged 41–93%, 29–94%, and 50–92%, for seed regions, end regions, and streamline maps, respectively. Differences in streamline maps correlated with differences in seed and end regions. Good inter-user agreement in seed and end regions, yielded inter-user reproducibility close to the intrinsic reproducibility (92–97%) and in most cases higher than 80%.

Discussion

Uncertainties related to user-dependent decisions and the probabilistic nature of the analysis should be considered when interpreting probabilistic tractography data. The standardization of the methods used to define seed and end regions is a necessary step to improve the accuracy and robustness of multi-fiber probabilistic tractography in a clinical setting. Clinical users should choose a feasible compromise between reproducibility and analysis duration.

  相似文献   
69.
70.
Language Resources and Evaluation - This work addresses some questions about language processing: what does it mean that natural language sentences are semantically complex? What semantic features...  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