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   101449篇
  免费   1938篇
  国内免费   538篇
电工技术   1075篇
综合类   2348篇
化学工业   15474篇
金属工艺   5305篇
机械仪表   3617篇
建筑科学   2523篇
矿业工程   602篇
能源动力   2466篇
轻工业   4729篇
水利工程   1390篇
石油天然气   427篇
武器工业   1篇
无线电   11455篇
一般工业技术   20213篇
冶金工业   4041篇
原子能技术   418篇
自动化技术   27841篇
  2024年   78篇
  2023年   422篇
  2022年   1004篇
  2021年   1180篇
  2020年   929篇
  2019年   957篇
  2018年   15280篇
  2017年   14038篇
  2016年   10711篇
  2015年   1191篇
  2014年   1074篇
  2013年   1729篇
  2012年   4005篇
  2011年   10329篇
  2010年   9011篇
  2009年   6296篇
  2008年   7426篇
  2007年   8262篇
  2006年   604篇
  2005年   1561篇
  2004年   1387篇
  2003年   1395篇
  2002年   727篇
  2001年   278篇
  2000年   353篇
  1999年   226篇
  1998年   357篇
  1997年   277篇
  1996年   281篇
  1995年   194篇
  1994年   180篇
  1993年   176篇
  1992年   122篇
  1991年   165篇
  1990年   104篇
  1989年   103篇
  1988年   90篇
  1987年   99篇
  1986年   79篇
  1985年   90篇
  1984年   80篇
  1983年   72篇
  1982年   61篇
  1981年   71篇
  1980年   58篇
  1968年   47篇
  1966年   43篇
  1965年   46篇
  1955年   63篇
  1954年   68篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
11.
Individually, photoredox catalysis (PC) and photodynamic therapy (PDT) are well-established concepts that have experienced a remarkable resurgence in recent years, leading to significant progress in organic synthesis for PC and clinical approval of anticancer drugs for PDT. But, very recently, new photoredox catalyst systems based on Ir(III) and Ru(II) complexes have garnered significant interest because they can simultaneously be used as PDT agents apart from their demonstrated PC activity. This highlight discusses the unique PC behavior of emerging Ir(III)- and Ru(II)-based systems while also examining their potential PDT activity in cancer treatment.  相似文献   
12.
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   
13.
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   
14.
Water Resources Management - The present study investigates and evaluate the scope and potential of modern computing tools and techniques such as ensembled machine learning methods in estimating...  相似文献   
15.
Wireless Personal Communications - Internet of Things (IoT) is one of the emerging technologies, which is widely used across the globe. As the idea of a smart city was founded, IoT has been...  相似文献   
16.
17.

ResearchGate has emerged as a popular professional network for scientists and researchers in a very short span. Similar to Google Scholar, the ResearchGate indexing uses an automatic crawling algorithm that extracts bibliographic data, citations, and other information about scholarly articles from various sources. However, it has been observed that the two platforms often show different publication and citation data for the same institutions, journals, and authors. While several previous studies analysed different aspects of ResearchGate and Google Scholar, the quantum of differences in publications, citations, and metrics between the two and the probable reasons for the same are not explored much. This article, therefore, attempts to bridge this research gap by analysing and measuring the differences in publications, citations, and different metrics of the two platforms for a large data set of highly cited authors. The results indicate that there are significantly high differences in publications and citations for the same authors captured by the two platforms, with Google Scholar having higher counts for a vast majority of the cases. The different metrics computed by the two platforms also differ in their values, showing different degrees of correlation. The coverage policy, indexing errors, author attribution mechanism, and strategy to deal with predatory publishing are found to be the main probable reasons for the differences in the two platforms.

  相似文献   
18.
ZnO rice like nonarchitects are grafted on the graphene carbon core via a rapid microwave synthesis route. The prepared grafted systems are characterized via XRD, SEM, RAMAN, and XPS to examined the structural and morphological parameters. Zinc oxide grafted graphene sheets (ZnO-G) are further doped in β-phase of polyvinylidene fluoride (PVDF) to prepare the polymer nanocomposites (PNCs) via mixed solvent approach (THF/DMF). β-phase confirmation of PVDF PNCs is done by FTIR studies. It is observed that ZnO-G filler enhances the β-phase content in the PNCs. Non-doped PVDF and PNCs are further studied for rheological behavior under the shear rate of 1–100 s−1. Doping of ZnO-G dopant to the PVDF matrix changes its discontinuous shear thickening (DST) behavior to continues shear thickening behavior (CST). Hydrocluster formation and their interaction with the dopant could be the reason for this striking DST to CST behavioral change. Strain amplitude sweep (10−3% -10%) oscillatory test reveals that the PNCs shows extended linear viscoelastic region with high elastic modulus and lower viscous modulus. Effective shear thickening behavior and strong elastic strength of these PNCs present their candidature for various fields including mechanical and soft body armor applications.  相似文献   
19.
Multimedia Tools and Applications - This paper presents early-automated glaucoma detection algorithm by extracting early diagnostic parameters, namely, parapapillary atrophy and Cup to Disc ratio...  相似文献   
20.
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