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   55158篇
  免费   1344篇
  国内免费   231篇
电工技术   778篇
综合类   645篇
化学工业   6720篇
金属工艺   941篇
机械仪表   1211篇
建筑科学   1036篇
矿业工程   462篇
能源动力   1097篇
轻工业   3193篇
水利工程   775篇
石油天然气   130篇
武器工业   4篇
无线电   3414篇
一般工业技术   6084篇
冶金工业   22921篇
原子能技术   379篇
自动化技术   6943篇
  2023年   363篇
  2022年   590篇
  2021年   585篇
  2020年   419篇
  2019年   451篇
  2018年   997篇
  2017年   1175篇
  2016年   1514篇
  2015年   1047篇
  2014年   856篇
  2013年   1277篇
  2012年   2638篇
  2011年   3084篇
  2010年   1194篇
  2009年   1273篇
  2008年   1065篇
  2007年   1004篇
  2006年   883篇
  2005年   3580篇
  2004年   2787篇
  2003年   2254篇
  2002年   1015篇
  2001年   871篇
  2000年   418篇
  1999年   768篇
  1998年   6494篇
  1997年   4028篇
  1996年   2746篇
  1995年   1664篇
  1994年   1246篇
  1993年   1266篇
  1992年   385篇
  1991年   452篇
  1990年   415篇
  1989年   381篇
  1988年   420篇
  1987年   328篇
  1986年   286篇
  1985年   281篇
  1984年   162篇
  1983年   187篇
  1982年   226篇
  1981年   263篇
  1980年   268篇
  1979年   113篇
  1978年   143篇
  1977年   664篇
  1976年   1395篇
  1975年   130篇
  1973年   75篇
排序方式: 共有10000条查询结果,搜索用时 875 毫秒
1.
2.
3.
The effect of microwave roasting parameters (300, 450 and 600 W; 5, 10 and 15 min) on acrylamide content in sorghum grain was determined using High Pressure Liquid Chromatography (HPLC)-photo diode array (PDA) detector coupled with C-18 column. Samples roasted at 300 and 450 W did not possess acrylamide, whereas 600 W (15 min) favoured formation of 2740.19 µg/kg of acrylamide, levels far exceeding the defined European Union (EU) limits. The chronic daily intake (CDI) for acrylamide through consumption of such grain flour was 3.25–9.5-fold higher to Joint FAO/WHO Expert Committee on Food Additives (JECFA) defined high exposure limits. The margin of exposure (MOE) values ranged from 4.3 to 12.76 and from 11.07 to 32.27 for neoplastic and neurological effects, respectively, demonstrating high exposure and serious health concerns associated with dietary intake of this toxicant. This study assesses the risk for the Indian population and highlights the importance of optimising process parameters for food product to minimise such exposure risks.  相似文献   
4.
Multimedia Tools and Applications - Currently, Deep Learning is playing an influential role for Image analysis and object classification. Maize’s diseases reduce production that subsequently...  相似文献   
5.

A large amount of data and applications need to be shared with various parties and stakeholders in the cloud environment for storage, computation, and data utilization. Since a third party operates the cloud platform, owners cannot fully trust this environment. However, it has become a challenge to ensure privacy preservation when sharing data effectively among different parties. This paper proposes a novel model that partitions data into sensitive and non-sensitive parts, injects the noise into sensitive data, and performs classification tasks using k-anonymization, differential privacy, and machine learning approaches. It allows multiple owners to share their data in the cloud environment for various purposes. The model specifies communication protocol among involved multiple untrusted parties to process owners’ data. The proposed model preserves actual data by providing a robust mechanism. The experiments are performed over Heart Disease, Arrhythmia, Hepatitis, Indian-liver-patient, and Framingham datasets for Support Vector Machine, K-Nearest Neighbor, Random Forest, Naive Bayes, and Artificial Neural Network classifiers to compute the efficiency in terms of accuracy, precision, recall, and F1-score of the proposed model. The achieved results provide high accuracy, precision, recall, and F1-score up to 93.75%, 94.11%, 100%, and 87.99% and improvement up to 16%, 29%, 12%, and 11%, respectively, compared to previous works.

  相似文献   
6.
7.
8.
In this study the effects of high temperature and moisture on the impact damage resistance and mechanical strength of Nextel 610/alumina silicate ceramic matrix composites were experimentally evaluated. Composite laminates were exposed to either a 1050°C isothermal furnace-based environment for 30 consecutive days at 6 h a day, or 95% relative humidity environment for 13 consecutive days at 67°C. Low velocity impact, tensile and short beam strength tests were performed on both ambient and environmentally conditioned laminates and damage was characterized using a combination of non-destructive and destructive techniques. High temperature and humidity environmental exposure adversely affected the impact resistance of the composite laminates. For all the environments, planar internal damage area was greater than the back side dent area, which in turn was greater than the impactor side dent area. Evidence of environmental embrittlement through a stiffer tensile response was noted for the high temperature exposed laminates while the short beam strength tests showed greater propensity for interlaminar shear failure in the moisture exposed laminates. Destructive evaluations exposed larger, more pronounced delaminations in the environmentally conditioned laminates in comparison to the ambient ones. External damage metrics of the impactor side dent depth and area directly influenced the post-impact tensile strength of the laminates while no such trend between internal damage area and residual strength could be ascertained.  相似文献   
9.
Multimedia Tools and Applications - The video surveillance activity generates a vast amount of data, which can be processed to detect miscreants. The task of identifying and recognizing an object...  相似文献   
10.
Silicon - Quadruple gate FinFET is a promising candidate among other multi-gate MOS devices due to it’s better scalability and higher short channel effect suppression capability in advanced...  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