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   1540篇
  免费   185篇
  国内免费   94篇
电工技术   35篇
综合类   50篇
化学工业   163篇
金属工艺   42篇
机械仪表   111篇
建筑科学   45篇
矿业工程   22篇
能源动力   83篇
轻工业   370篇
水利工程   7篇
石油天然气   30篇
武器工业   5篇
无线电   155篇
一般工业技术   137篇
冶金工业   40篇
原子能技术   13篇
自动化技术   511篇
  2024年   2篇
  2023年   64篇
  2022年   75篇
  2021年   86篇
  2020年   78篇
  2019年   63篇
  2018年   64篇
  2017年   86篇
  2016年   71篇
  2015年   64篇
  2014年   110篇
  2013年   112篇
  2012年   196篇
  2011年   153篇
  2010年   96篇
  2009年   112篇
  2008年   65篇
  2007年   103篇
  2006年   74篇
  2005年   27篇
  2004年   17篇
  2003年   14篇
  2002年   26篇
  2001年   14篇
  2000年   7篇
  1999年   16篇
  1998年   10篇
  1997年   1篇
  1996年   2篇
  1995年   5篇
  1994年   3篇
  1992年   1篇
  1989年   1篇
  1988年   1篇
排序方式: 共有1819条查询结果,搜索用时 15 毫秒
1.
以“创新、协调、绿色、开放、共享”为内核的新发展理念,是对马克思主义发展理念的继承和发扬,极具时代精神,富含问题意识,为高校思想政治教育发展、教育教学改革实践提供了强大的理论支撑。本文以“通信原理”为例,阐述了新发展理念在课程改革中的思路和方法,实现了思想政治教育与专业基础课程有机融合,为深化高校教学改革、创新人才培养模式提供了思路。  相似文献   
2.
3.
4.
The naked barley was germinated and then carried out with hot air- or infrared drying to explore the physicochemical and functional properties of protein isolated from barley. Moreover, the relationship between protein and the noodles made from wheat and germinated barley flour was evaluated. It was found that germination affected the protein properties, and the protein properties were correlated with the properties of noodles. The content of β-sheet in protein was first increased and then decreased with germination time increased, and the protein had larger emulsification and foaming properties. Besides, the protein isolated from hot air-dried germinated barley had higher gelatinisation enthalpy and secondary structure content. Furthermore, the wheat and germinated barley mixed noodles had increased elasticity and cohesiveness and reduced viscosity and water absorption. The hardness of noodles showed was positively correlated with water absorption capacity, and the extensibility of cooked noodles was positively correlated with the foaming capacity of proteins.  相似文献   
5.
《Planning》2019,(5)
目的探讨彩色多普勒超声测量肾脏叶间动脉阻力指数(resistance index,RI)对Ⅰ型心肾综合征(cardiorenal syndrome,CRS)的诊断价值。方法选取2017年6月1日至2018年3月1日收住民航总医院急诊综合病房并诊断为Ⅰ型CRS的20例患者作为试验组(CRS组),选取同期诊断为单纯急性心力衰竭的患者20例作为对照组,分析两组患者的临床特征、实验室检查及用药情况,并根据受试者工作特征(receiver operating characteristic,ROC)曲线评价肾动脉RI对Ⅰ型CRS的诊断价值。结果两组患者年龄、左心室射血分数、心功能分级、心率及脉压差差异无统计学意义(P均>0. 05),CRS组患者的氨基末端脑钠尿肽、肌酐水平、呋塞米剂量以及肾动脉RI均高于对照组,而肾小球滤过率低于对照组,差异具有统计学意义(P均<0. 05)。ROC曲线下面积为0. 78,取最佳截点值0. 70时预测Ⅰ型CRS的敏感度为80%,特异度为80%。结论作为一种新的手段,肾动脉RI可与传统方法相互补充,对诊断Ⅰ型心肾综合征患者具有潜在应用价值。  相似文献   
6.
This paper illustrates whether the availability of online content of local interest affects the likelihood of individuals to connect to the internet and spend more time online. While the literature demonstrates a number of factors which push or enable individuals to spend more time online, we know little about the conditions that pull or attract individuals online. Although we know that individuals use the internet to access information, we do not know whether such attraction forces are relevant at the local scale too. Gaining a better understanding of how such mechanisms work at the local scale can assist our efforts to bridge digital divides, which tend to be geographically clustered. To explore this we utilise innovative data, which contain all the archived webpages under the UK top level domain name (.uk) and we calculate the volume of internet content of local interest at the neighbourhood level using the geolocation information included in the text of these webpages. Specifically, we calculate the radius of gyration for every archived website using the different postcodes included in the archived webpages and then we create an aggregated measure at the neighbourhood level discounting websites that have less of a local focus. We merge this measure of Local Internet Content (LIC) with a large population survey, which contains information about the frequency of internet usage in the UK and estimate the effect of LIC on the likelihood of an individual being a frequent internet user. Multilevel models are employed to utilise both individual and geographical level characteristics. Our results indicate that even after controlling for the individual and geographical characteristics, which according to previous studies affect internet usage, the availability of internet content of local interest still attracts individuals online.  相似文献   
7.
Guo  Zhide  Yang  Liu  Chen  Mei  Wen  Xuejun  Liu  Huanhuan  Li  Jingchao  Xu  Duo  An  Yuanyuan  Shi  Changrong  Li  Jindian  Su  Xinhui  Li  Zijing  Liu  Ting  Zhuang  Rongqiang  Zheng  Nanfeng  Zhu  Haibo  Zhang  Xianzhong 《Nano Research》2020,13(1):173-182

Vulnerable atherosclerotic plaques are responsible for most cardiovascular diseases (CVDs). Folate receptor (FR) positive activated macrophages were thought to be a prominent component in the development of vulnerable plaque. The objective of this study is to develop folate conjugated two-dimensional (2D) Pd@Au nanomaterials (Pd@Au-PEG-FA) for targeted multimodal imaging of the FRs in advanced atherosclerotic plaques. Pharmacokinetic and imaging studies (single photon emission computed tomography (SPECT), computed tomography (CT) and photoacoustic (PA) imaging) were performed to confirm the prolonged blood half-life and enrichment of radioactivity in atherosclerotic plaques. Strong signals were detected in vivo with SPECT, CT and PA imaging in heavy atherosclerotic plaques, which were significantly higher than those of the normal aortas after injection of Pd@Au-PEG-FA. Blocking studies with preinjection of excess FA could effectively reduce the targeting ability of Pd@Au-PEG-FA in atherosclerotic plaques, further demonstrating the specific binding of Pd@Au-PEG-FA for plaque lesions. Histopathological characterization revealed that the signal of probe was in accordance with the high-risk plaques. In summary, the Pd@Au-PEG-FA has favorable pharmacokinetic properties and provides a valuable approach for detecting high-risk plaques in the presence of FRs in atherosclerotic plaques.

  相似文献   
8.
Wang  Xue  Yang  Xuemei  Du  Jian  Wang  Xuwen  Li  Jiao  Tang  Xiaoli 《Scientometrics》2021,126(7):5531-5549
Scientometrics - Breakthrough research in scientific fields usually comes as a manifestation of major development and advancement. These advances build to an epiphany where new ways of thinking...  相似文献   
9.
The performance of conventional computer based on von Neumann architecture is limited due to the physical separation of memory and processor. By synergistically integrating various sensors with synaptic devices, recently emerging interactive neuromorphic devices can directly sense/store/process various stimuli information from external environments and implement functions of perception, learning, memory, and computation. In this review, we present the basic model of bioinspired interactive neuromorphic devices and discuss the performance metrics. Next, we summarize the recent progress and development of bioinspired interactive neuromorphic devices, which are classified into neuromorphic tactile systems, visual systems, auditory systems, and multisensory system. They are discussed in detail from the aspects of materials, device architectures, operating mechanisms, synaptic plasticity, and potential applications. Additionally, the bioinspired interactive neuromorphic devices that can fuse multiple/mixed sensing signals are proposed to address more realistic and sophisticated problems. Finally, we discuss the pros and cons regarding to the computing neurons and integrating sensory neurons and deliver the perspectives on interactive neuromorphic devices at the material, device, network, and system levels. It is believed the neuromorphic devices can provide promising solutions to next generation of interactive sensation/memory/computation toward the development of multimodal, low-power, and large-scale intelligent systems endowed with neuromorphic features.  相似文献   
10.
Clustering of datain alarge di mensionspaceis ofa great interest in many data mining applications .Clustering methods have been studiedin several areasincluding statistics , machine learning and data min-ing. Most of the algorithms are effective whenthe di-mensionality of the datais relativelysmall .But ,theseschemes tend to break down when the di mensionalityof the datais very high.There are several reasons[1].First ,it is not trivial to define distance measure in alarge di mensional space .…  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