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   7420篇
  免费   589篇
  国内免费   211篇
电工技术   415篇
技术理论   1篇
综合类   492篇
化学工业   1272篇
金属工艺   292篇
机械仪表   386篇
建筑科学   481篇
矿业工程   208篇
能源动力   203篇
轻工业   700篇
水利工程   126篇
石油天然气   446篇
武器工业   52篇
无线电   660篇
一般工业技术   895篇
冶金工业   616篇
原子能技术   49篇
自动化技术   926篇
  2024年   24篇
  2023年   107篇
  2022年   185篇
  2021年   271篇
  2020年   191篇
  2019年   179篇
  2018年   229篇
  2017年   243篇
  2016年   225篇
  2015年   267篇
  2014年   370篇
  2013年   475篇
  2012年   474篇
  2011年   517篇
  2010年   426篇
  2009年   394篇
  2008年   407篇
  2007年   385篇
  2006年   401篇
  2005年   298篇
  2004年   224篇
  2003年   204篇
  2002年   181篇
  2001年   199篇
  2000年   164篇
  1999年   177篇
  1998年   251篇
  1997年   177篇
  1996年   123篇
  1995年   102篇
  1994年   84篇
  1993年   61篇
  1992年   33篇
  1991年   25篇
  1990年   18篇
  1989年   19篇
  1988年   20篇
  1987年   11篇
  1986年   9篇
  1985年   6篇
  1984年   3篇
  1983年   10篇
  1982年   9篇
  1980年   3篇
  1979年   5篇
  1978年   3篇
  1977年   10篇
  1976年   11篇
  1975年   2篇
  1974年   3篇
排序方式: 共有8220条查询结果,搜索用时 31 毫秒
51.
52.
穆东 《特殊钢》1997,18(4):21-25
衡阳钢管厂Φ89mm半浮芯棒连轧管机组是一种新型机组,其选配的变形工艺路线能很好地适应生产小规格的热轧无缝钢管。本文论述了该机组的工艺及设备结构特点。  相似文献   
53.
Spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats that had been on a low sodium diet for 3 days were given 1.5 mmol sodium chloride kg-1 body weight either orally or intravenously. The rats receiving an oral sodium load showed a greater natriuresis than those receiving the same saline load intravenously. No increase of renal sodium excretion was observed when the rats received a hypertonic mannitol solution orally. The cumulative sodium excretion during the 8 h following oral loading was two to three times larger in SHR than in WKY, whereas no difference between strains could be demonstrated after giving saline intravenously. Furthermore, after switching from normal to low sodium diet the rate of decrease of renal sodium excretion was greater in SHR than in WKY rats. It is proposed that there exists a gastrointestinal sensory mechanism for sodium controlling the renal sodium excretion. Furthermore, it is suggested that the function of this mechanism differs between SHR and WKY.  相似文献   
54.
The fibrinolytic capacity of patients with acute myocardial infarction (AMI) is known to be impaired. The primary regulatory element of the fibrinolytic system is plasminogen activator inhibitor (PAI). It has been previously observed that there are 2 peaks in the plasma PAI level of AMI patients at 4h and 16h after thrombolytic therapy with recombinant tissue plasminogen activator (rtPA). Lanoteplase/SUN9216 is a mutant tPA with a biological half-life longer than that of rtPA. Thrombolytic therapy with mutant tPA or rtPA was carried out consecutively in 21 patients with AMI (8 patients as the mutant tPA group, and 13 patients as the rtPA group). The recanalization time of the mutant tPA group was significantly faster than that of the rtPA group (16.1 +/- 3.9 min vs 39.6 +/- 4.8 min, p<0.01). The PAI activity at 4h after the initiation of thrombolysis was significantly lower in the mutant tPA group than in the rtPA group (8.74 +/- 5.46IU/L vs 26.74 +/- 3.35 IU/L, p<0.01). There was a one mild peak in serial plasma PAI activity levels 24h after the initiation of thrombolysis. The results suggest that thrombolytic therapy with mutant tPA reduced the impairment of fibrinolytic capacity. The mutant tPA gives faster recanalization and lower PAI activity after successful thrombolysis, compared with rtPA.  相似文献   
55.
56.
Winner-Take-All (WTA) or K-Winner-Take-All (KWTA) networks have been frequently used as the basic building blocks of complex neural networks. This paper introduces a new selection rule for network connections that implements stable KWTA networks. To widen the applications of WTA networks, a new class of WTA networks is proposed, and their efficient design methods are presented. We demonstrate the properties of the generalized class of WTA networks, through three application examples.  相似文献   
57.
本文研究了TiO2掺入对CaO稳定ZrO2(简称CaSZ-NiCr)金属陶瓷烧结特性的影响,测定了CaSZ-NiCr-TiO2金属陶瓷烧结样品的密度和显微硬度,结果表明,TiO2的掺入能提高CaSZ-NICr金属陶瓷的烧结密度和显微硬度,对CaSZ-NiCr金属陶瓷有助烧结作用.金相观察表明,TiO3的掺入改变了NiCr相在金属陶瓷中的形貌,说明了NiCr与CaSZ的浸润性有一定的改善.XRD和EPMA分析结果显示,TiO2偏聚在NiCr金属相中,不影响CaSZ的稳定性.  相似文献   
58.
The rapidly increasing popularity of mobile devices has changed the methods with which people access various network services and increased network traffic markedly. Over the past few decades, network traffic identification has been a research hotspot in the field of network management and security monitoring. However, as more network services use encryption technology, network traffic identification faces many challenges. Although classic machine learning methods can solve many problems that cannot be solved by port- and payload-based methods, manually extract features that are frequently updated is time-consuming and labor-intensive. Deep learning has good automatic feature learning capabilities and is an ideal method for network traffic identification, particularly encrypted traffic identification; Existing recognition methods based on deep learning primarily use supervised learning methods and rely on many labeled samples. However, in real scenarios, labeled samples are often difficult to obtain. This paper adjusts the structure of the auxiliary classification generation adversarial network (ACGAN) so that it can use unlabeled samples for training, and use the wasserstein distance instead of the original cross entropy as the loss function to achieve semisupervised learning. Experimental results show that the identification accuracy of ISCX and USTC data sets using the proposed method yields markedly better performance when the number of labeled samples is small compared to that of convolutional neural network (CNN) based classifier.  相似文献   
59.
The Journal of Supercomputing - In this paper, we propose a parallel source separation system designed to extract heart and lung sounds from single-channel mixtures. The proposed system is based on...  相似文献   
60.
Mu  Dongdong  Wang  Guofeng  Fan  Yunsheng 《Neural computing & applications》2021,33(19):12777-12789
Neural Computing and Applications - In this paper, one concerns with the problem of trajectory tracking control for an underactuated unmanned surface vehicle subject to uncertain dynamics and input...  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