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   1529120篇
  免费   28113篇
  国内免费   7066篇
电工技术   34653篇
综合类   6406篇
化学工业   274249篇
金属工艺   64957篇
机械仪表   43671篇
建筑科学   46295篇
矿业工程   11526篇
能源动力   51045篇
轻工业   112608篇
水利工程   15566篇
石油天然气   37913篇
武器工业   132篇
无线电   198778篇
一般工业技术   289010篇
冶金工业   171650篇
原子能技术   34225篇
自动化技术   171615篇
  2021年   16287篇
  2020年   12495篇
  2019年   15314篇
  2018年   17740篇
  2017年   17043篇
  2016年   22443篇
  2015年   17799篇
  2014年   29162篇
  2013年   88598篇
  2012年   36355篇
  2011年   49607篇
  2010年   43809篇
  2009年   52088篇
  2008年   45679篇
  2007年   43056篇
  2006年   44780篇
  2005年   39921篇
  2004年   41817篇
  2003年   41735篇
  2002年   40552篇
  2001年   37458篇
  2000年   35867篇
  1999年   35207篇
  1998年   48209篇
  1997年   40871篇
  1996年   36320篇
  1995年   31229篇
  1994年   29206篇
  1993年   29122篇
  1992年   26177篇
  1991年   23314篇
  1990年   23668篇
  1989年   22723篇
  1988年   21227篇
  1987年   19509篇
  1986年   18860篇
  1985年   22177篇
  1984年   22348篇
  1983年   20254篇
  1982年   19253篇
  1981年   19394篇
  1980年   17966篇
  1979年   18451篇
  1978年   17710篇
  1977年   17476篇
  1976年   18403篇
  1975年   15977篇
  1974年   15466篇
  1973年   15577篇
  1972年   12992篇
排序方式: 共有10000条查询结果,搜索用时 929 毫秒
21.
Theoretical Foundations of Chemical Engineering - On the basis of the classic concepts of the theory of solid-phase combustion, for the first time, a model with a detailed scheme of chemical...  相似文献   
22.
23.
Multimedia Tools and Applications - Recently, many concepts in technology has been changed. According to the digital transformation trends, Internet of Things (IoT) represents an interested...  相似文献   
24.
In this study, dilute chemical bath deposition technique has been used to deposit CdZnS thin films on soda-lime glass substrates. The structural, morphological, optoelectronic properties of as-grown films have been investigated as a function of different Zn2+ precursor concentrations. The X-ray diffractogram of CdS thin-film reveals a peak corresponding to (002) plane with wurtzite structure, and the peak shift has been observed with the increase of the Zn2+ concentration upon formation of CdZnS thin film. From morphological studies, it has been revealed that the diluted chemical bath deposition technique provides homogeneous distribution of film on the substrate even at a lower concentration of Zn2+. Optical characterization has shown that the transparency of the film is influenced by Zn2+ concentration and when the Zn2+ concentration is varied from 0 M to 0.0256 M, bandgap values of resulting films range from 2.42 eV to 3.90 eV while. Furthermore, electrical properties have shown that with increasing zinc concentration the resistivity of the film increases. Finally, numerical simulation validates and suggests that CdZnS buffer layer with composition of 0.0032 M Zn2+ concentration would be a promising candidate in CIGS solar cell.  相似文献   
25.
Combustion, Explosion, and Shock Waves - Results of a numerical study of mixing, ignition, and combustion of a cold hydrogen jet propagating along the lower wall of a channel parallel to a...  相似文献   
26.
Multimedia Tools and Applications - In this work, a new fuzzy logic-based algorithm is proposed for the enhancement of low light color images. A generalization of a fuzzy set known as an...  相似文献   
27.
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   
28.
Wireless Personal Communications - In the present scenario, there is a boom in the demand of the users to achieve increased capacity, high data, low latency, and high-performance rates. 5G New...  相似文献   
29.

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   
30.
Multimedia Tools and Applications - The three-dimensional models of brain tumors serve as diagnostic assistance for physicians, surgeons, and radiologists. The proposed system establishes an...  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