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   801203篇
  免费   10842篇
  国内免费   2427篇
电工技术   14669篇
综合类   744篇
化学工业   119924篇
金属工艺   30780篇
机械仪表   24290篇
建筑科学   18642篇
矿业工程   3932篇
能源动力   22226篇
轻工业   64774篇
水利工程   8165篇
石油天然气   14361篇
武器工业   48篇
无线电   93098篇
一般工业技术   157626篇
冶金工业   156321篇
原子能技术   16298篇
自动化技术   68574篇
  2022年   4810篇
  2021年   7344篇
  2020年   5507篇
  2019年   6964篇
  2018年   11889篇
  2017年   11704篇
  2016年   12408篇
  2015年   8357篇
  2014年   13796篇
  2013年   37956篇
  2012年   21822篇
  2011年   29972篇
  2010年   23742篇
  2009年   26803篇
  2008年   27283篇
  2007年   27027篇
  2006年   23805篇
  2005年   21593篇
  2004年   20643篇
  2003年   20487篇
  2002年   19316篇
  2001年   19277篇
  2000年   17986篇
  1999年   19047篇
  1998年   48976篇
  1997年   34304篇
  1996年   26331篇
  1995年   19694篇
  1994年   17141篇
  1993年   16958篇
  1992年   12225篇
  1991年   11399篇
  1990年   11319篇
  1989年   10877篇
  1988年   10063篇
  1987年   9032篇
  1986年   8828篇
  1985年   9828篇
  1984年   9086篇
  1983年   8134篇
  1982年   7571篇
  1981年   7689篇
  1980年   7229篇
  1979年   7073篇
  1978年   6877篇
  1977年   8154篇
  1976年   10692篇
  1975年   5935篇
  1974年   5553篇
  1973年   5718篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
Class I hydrophobin Vmh2, a peculiar surface active and versatile fungal protein, is known to self‐assemble into chemically stable amphiphilic films, to be able to change wettability of surfaces, and to strongly adsorb other proteins. Herein, a fast, highly homogeneous and efficient glass functionalization by spontaneous self‐assembling of Vmh2 at liquid–solid interfaces is achieved (in 2 min). The Vmh2‐coated glass slides are proven to immobilize not only proteins but also nanomaterials such as graphene oxide (GO) and quantum dots (QDs). As models, bovine serum albumin labeled with Alexa 555 fluorophore, anti‐immunoglobulin G antibodies, and cadmium telluride QDs are patterned in a microarray fashion in order to demonstrate functionality, reproducibility, and versatility of the proposed substrate. Additionally, a GO layer is effectively and homogeneously self‐assembled onto the studied functionalized surface. This approach offers a quick and simple alternative to immobilize nanomaterials and proteins, which is appealing for new bioanalytical and nanobioenabled applications.  相似文献   
132.
133.
134.
135.
136.
137.
138.
ABSTRACT

This paper proposes the multiple-hypotheses image segmentation and feed-forward neural network classifier for food recognition to improve the performance. Initially, the food or meal image is given as input. Then, the segmentation is applied to identify the regions, where a particular food item is located using salient region detection, multi-scale segmentation, and fast rejection. Then, the features of every food item are extracted by the global feature and local feature extraction. After the features are obtained, the classification is performed for each segmented region using a feed-forward neural network model. Finally, the calorie value is computed with the aid of (i) food volume and (ii) calorie and nutrition measure based on mass value. The experimental results and performance evaluation are validated. The outcome of the proposed method attains 0.947 for Macro Average Accuracy (MAA) and 0.959 for Standard Accuracy (SA), which provides better classification performance.  相似文献   
139.
140.
Wastewater treatment plant operators encounter complex operational problems related to the activated sludge process and usually respond to these by applying their own intuition and by taking advantage of what they have learnt from past experiences of similar problems. However, previous process experiences are not easy to integrate in numerical control, and new tools must be developed to enable re-use of plant operating experience. The aim of this paper is to investigate the usefulness of a case-based reasoning (CBR) approach to apply learning and re-use of knowledge gained during past incidents to confront actual complex problems through the IWA/COST Benchmark protocol. A case study shows that the proposed CBR system achieves a significant improvement of the benchmark plant performance when facing a high-flow event disturbance.  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