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   1393篇
  免费   72篇
  国内免费   40篇
电工技术   91篇
综合类   77篇
化学工业   27篇
金属工艺   47篇
机械仪表   103篇
建筑科学   20篇
矿业工程   38篇
能源动力   18篇
轻工业   11篇
水利工程   6篇
石油天然气   4篇
武器工业   7篇
无线电   351篇
一般工业技术   19篇
冶金工业   130篇
原子能技术   5篇
自动化技术   551篇
  2023年   2篇
  2022年   6篇
  2021年   14篇
  2020年   16篇
  2019年   14篇
  2018年   9篇
  2017年   35篇
  2016年   41篇
  2015年   61篇
  2014年   132篇
  2013年   92篇
  2012年   192篇
  2011年   189篇
  2010年   143篇
  2009年   161篇
  2008年   90篇
  2007年   75篇
  2006年   37篇
  2005年   25篇
  2004年   24篇
  2003年   15篇
  2002年   36篇
  2001年   34篇
  2000年   20篇
  1999年   13篇
  1998年   5篇
  1997年   7篇
  1996年   6篇
  1995年   5篇
  1994年   4篇
  1993年   1篇
  1991年   1篇
排序方式: 共有1505条查询结果,搜索用时 31 毫秒
1.
Previous studies reported coastal trapped waves (CTWs) in the Caspian Sea (CS). This study deals with the generation mechanisms, the temporal and spatial variability of CTWs in this area, and their transformations during propagation from the origin to the destination using recent measurements and high-resolution numerical simulations. CTWs are observed at all stations with periods of 2–6 days after northerly storms. The Absheron Peninsula, old Sefidrud delta, and Nur coasts were identified as the CTWs prone regions. The generation of CTWs in these locations was confirmed using numerical experiments. The propagation away from the generating location of CTWs was analyzed using a representative real wind storm. In the west part of the CS, the generation mechanism of CTWs is mainly similar to the barotropic Kelvin waves; in contrast, it is similar to the continental shelf waves in the southern shelves. The results can be used to study the contribution of generated CTWs to the transport of sediment and biological materials in all large lakes.  相似文献   
2.
Tong MA  Fafen WANG  Xiaohui WANG 《Biocell》2019,43(3):191-198
Cervical cancer (CC), has been identified as one of the most frequent malignant tumors all over the world, with high mortality in females. A growing number of investigations have confirmed that long noncoding RNAs (lncRNAs) play a crucial role in the progression of multiple cancers. Nonetheless, the biological function and regulatory mechanism of LINC01772 in CC haven’t been explored so far. In this study, LINC01772 expression was found to be upregulated in tissues and cells of CC. Knocking down LINC01772 suppressed CC cell proliferation, migration and epithelial-mesenchymal transition (EMT) process. Through molecular mechanism assays, LINC01772 was verified to be bound with miR-3611 and LINC01772 acted as a sponge for miR-3611. Zinc finger E-box binding homeobox 1 (ZEB1) was a downstream target gene of miR-3611. ZEB1 was negatively regulated by miR-3611 but positively regulated by LINC01772. Rescue assays confirmed that miR-3611 inhibitor or ZEB1 overexpression offset the inhibitive effect of LINC01772 depletion on cell proliferation, migration and EMT process in CC. In a word, our study validated that LINC01772 promoted cell metastasis and EMT process in CC by sponging miR-3611 to upregulate ZEB1 expression, indicating that LINC01772 could serve as a new therapeutic target for patients with CC.  相似文献   
3.
目的对创造性4C认知量表(CC4CS)在中国大学生中进行修订,以便探讨创造性4C理论在中国本土文化中的适用性。方法从在线大学生QQ群中招募全国各地3 360名在校大学生为被试,填写CC4CS中文版初测量表,分析其信效度。结果 (1)各项目的区分度与鉴别性较好(t=14.01~34.77,r=0.31~0.55,P均0.001)。(2)经探索性因子分析,得到与原量表一致的创造性4C结构,累积方差解释率为55.22%。(3)总量表Cronbachα系数为0.85,重测信度为0.88,各分量表的α系数在0.72~0.82之间,重测信度在0.81~0.90之间;与Lawdsei认知创造力量表和Rudowicz-Hui创造力概念调查量表的关联效度分别为0.67、0.77;各分量表与总分以及各分量表之间的相关分别在0.53~0.74、0.10~0.60之间,结构效度良好。结论 CC4CS中文版具有较好的心理测量学指标,适用于在中国文化背景下大学生的创造性4C认知测量。  相似文献   
4.
Precombustion carbon capture is an effective strategy to reduce large-scale CO2 emissions, which is mainly used in the area of integrated gasification combined cycle (IGCC) power plants. Oxygen transport membranes (OTMs) were suggested as the air separation unit to produce high purity oxygen for the gasifier. However, the improvement in efficiency was limited. Here, a new IGCC process is reported based on a robust OTM reactor, where the OTM reactor is used behind the coal gasifier. This IGCC-OTM process fulfills syngas oxidation, H2 production, and carbon capture in one unit, thus a significant decrease of the energy penalty is expectable. The membrane reactor does not use noble metal components, and exhibits high hydrogen production rates, high hydrogen separation factor (103–104), and stable performance in a gas mixture mimicking real syngas compositions from a coal gasifier with H2S concentrations up to 1,000 ppm.  相似文献   
5.
通过制定通信协议,将现场采集的数据以无线数字方式传输到主控室的上位机,实现了在远离生产现场的控制室对现场的温度、湿度、流量等进行监控,并经模拟运行证实。  相似文献   
6.
An evaluation model for individual thermal comfort is presented based on the BP neural network. The train data came from a thermal comfort survey. The evaluation results of the model showed a good match with the subject's real thermal sensation, which indicated that the model can be used to evaluate individual thermal comfort rightly. Taken a room air conditioner as an example, the application of the NNEM in creating a microenvironment for individual was discussed. The result showed that the NNEM can play an important role of connecting individual thermal comfort with the control on the air conditioner.  相似文献   
7.
8.
周干武  郦能惠  何宁 《岩土工程学报》2014,36(12):2330-2334
构建了基于物联网技术的土石坝安全监测自动化系统,利用无线传感网芯片CC2530和GPRS模块完成了传感器节点、路由器节点、协调节点的硬件和软件设计,集成无线传感网和地理信息系统。实现对土石坝大坝变形、渗流、应力应变以及环境气象等各种因子进行全天候的实时监测、采集和控制,并在专家知识库辅助下,实现对土石坝安全性状的智能化、科学化管理。  相似文献   
9.
太阳能电池板分布密集,针对传统方式监测太阳能电池板温度布线困难。为了更加高效便捷获取太阳能电池板的表面温度,设计一种无线测温装置可以同时监测10块太阳能电池板的实时温度。利用数字温度传感器DS18B20进行测温,超低功耗16位单片机MSP430F149进行数据处理并且利用无线模块CC1101进行数据的传输,最终将太阳能电池板的温度数据显示到液晶屏上。经实际测试,无线传输距离可达50 m,精度可达0.1℃,可以同时监测10块太阳能电池板温度数据,且系统具有传输稳定、功耗低、成本低等优点。  相似文献   
10.
为了提高电力设备状态监控的可靠性和便捷性,针对传统的有线网络采集布线复杂和成本高的缺点,设计了一种基于ZigBee无线网络的电力设备远程监控系统。利用TI公司片上系统CC2530芯片作为ZigBee网络的路由器,通过RS485-RS232协议转换器将电表数据读入ZigBee网络,再利用片上系统CC2538芯片作为ZigBee网络的协调器,接收底层模块的数据并将数据上传至上位机以实现数据监控。采用了一种协调器单次问询,从设备周期性回复的通信方式,并在协调器中实现了数据存储、问询判断、掉线重发等功能以使整个系统协同,高效的工作。  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