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   95480篇
  免费   17306篇
  国内免费   11867篇
电工技术   6482篇
技术理论   2篇
综合类   10160篇
化学工业   4373篇
金属工艺   1327篇
机械仪表   3204篇
建筑科学   1018篇
矿业工程   1077篇
能源动力   2315篇
轻工业   903篇
水利工程   339篇
石油天然气   475篇
武器工业   553篇
无线电   25934篇
一般工业技术   6214篇
冶金工业   540篇
原子能技术   214篇
自动化技术   59523篇
  2024年   300篇
  2023年   3289篇
  2022年   4863篇
  2021年   5598篇
  2020年   5659篇
  2019年   4426篇
  2018年   4467篇
  2017年   5861篇
  2016年   5899篇
  2015年   5957篇
  2014年   8396篇
  2013年   8467篇
  2012年   11030篇
  2011年   10408篇
  2010年   8178篇
  2009年   8171篇
  2008年   5819篇
  2007年   6038篇
  2006年   4738篇
  2005年   2317篇
  2004年   908篇
  2003年   847篇
  2002年   805篇
  2001年   684篇
  2000年   543篇
  1999年   303篇
  1998年   110篇
  1997年   83篇
  1996年   97篇
  1995年   43篇
  1994年   42篇
  1993年   38篇
  1992年   27篇
  1991年   26篇
  1990年   20篇
  1989年   18篇
  1988年   14篇
  1987年   14篇
  1986年   44篇
  1985年   20篇
  1984年   15篇
  1983年   8篇
  1982年   9篇
  1981年   11篇
  1980年   7篇
  1979年   7篇
  1978年   5篇
  1977年   8篇
  1976年   3篇
  1974年   3篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Shen  Aiguo  Ye  Qiubo  Yang  Guangsong  Hao  Xinyu 《Telecommunication Systems》2021,78(4):629-643
Telecommunication Systems - Machine to Machine technology has a broad application prospect in the 5G network, but there is a bottleneck in the energy consumption of intelligent devices powered by...  相似文献   
2.
Due to the limited improvement of single-image based super-resolution (SR) methods in recent years, the reference based image SR (RefSR) methods, which super-resolve the low-resolution (LR) input with the guidance of similar high-resolution (HR) reference images are emerging. There are two main challenges in RefSR, i.e. reference image warping and exploring the guidance information from the warped references. For reference warping, we propose an efficient dense warping method to deal with large displacements, which is much faster than traditional patch (or texture) matching strategy. For the SR process, since different reference images complement each other, and have different similarities with the LR image, we further propose a similarity based feature fusion strategy to take advantage of the most similar reference regions. The SR process is realized by an encoder–decoder network and trained with pixel-level reconstruction loss, degradation loss and feature-level perceptual loss. Extensive experiments on three benchmark datasets demonstrate that the proposed method outperforms state-of-the-art SR methods in both subjective and objective measurements.  相似文献   
3.
The applications of antiferroelectric (AFE) materials in miniaturized and integrated electronic devices are limited by their low energy density. To address the above issue, the antiferroelectricity of the reinforced material was designed to improve its AFE-ferroelectric (FE) phase transition under electric fields. In this present study, the composition of Zr4+ (0.72 Å) and Ti4+ (0.605 Å) at B-site of Pb0.97La0.02(ZrxSn0.05Ti0.95-x)O3 ceramics with orthogonal reflections are synthesized via the tape-casting method. These ceramics are modified to enhance their antiferroelectricity by reducing their tolerance factor. A recoverable energy storage density Wrec 12.1 J/cm3 was obtained for x = 0.93 under 376 kV/cm, which is superior value than reported until now in lead-based energy storage systems. Moreover, the discharge energy density can reach 10.23 J/cm3, and 90 % of which can be released within 5.66 μs. This work provides a new window and potential materials for further industrialization of pulse power capacitors.  相似文献   
4.
5.
Power conversion efficiency (PCE) and stability are two important properties of perovskite solar cells (PSCs). Particularly, defects in the perovskite films could cause the generation of trap states, thereby increasing the nonradiative recombination. To address this issue, suitable dopants can be incorporated to react with non-bonded atoms or surface dangling bonds to passivate the defects. Herein, we introduced TiI4 into CH3NH3PbI3 (MAPbI3) film and obtained a dense and uniform morphology with large crystal grains and low defect density. The champion cell based on 0.5% TiI4-doped MAPbI3 achieved a PCE as high as 20.55%, which is superior to those based on pristine MAPbI3 (17.64%). Moreover, the optimal solar cell showed remarkable stability without encapsulation. It retained 88.03% of its initial PCE after 300 h of storage in ambient. This work demonstrates TiI4 as a new and effective passivator for MAPbI3 film.  相似文献   
6.
肖雄亮  陈长明 《红外技术》2021,43(12):1228-1233
设计了由光源、气室、探测器和控制器等组成的非分散红外吸收系统,往气室内通入不同浓度的多组分气体(含有乙醇、二氧化碳和水蒸气),采用红外光谱仪进行光谱数据采集,得到多组分气体混合光谱图。根据数据集样本求解回归系数,建立了多元线性回归模型,并进行干扰修正以降低二氧化碳和水蒸气对乙醇浓度预测的影响。对建立的多元线性回归模型进行评价,结果表明:模型真实有效且具有良好的线性回归效果,可以用于预测气体浓度,乙醇、二氧化碳和水蒸气浓度预测误差均在可接受的范围之内,其中乙醇浓度预测误差最小,不超过2.0×10-4。通过干扰修正尽可能排除二氧化碳和水蒸气的干扰,能够较准确地预测乙醇浓度。  相似文献   
7.
引入句法依存信息到原方面术语,提出一种新的方面术语表示方法,利用Glove词向量表示单词以及单词与单词之间的依存关系,构造出包含句法依存信息的依存关系邻接矩阵和依存关系表示矩阵,利用图卷积神经网络和多头注意力机制将句法依存信息融入到方面术语中,使得方面术语表达与上下文结构高度相关。将改进后的方面词术语表示替换到现有模型后,模型泛化能力得到有效提升。对比试验和分析结果表明:该方法具有有效性和泛化性。  相似文献   
8.
The audit point is to understand and use to perform the upgrade wearable innovation injuries in sports. Understanding the game's biomechanics is that damage response and performance upgrades are essential, and usually, investigation uses optical motion capture. In any case, this approach may be limited by the amount of limit catch climatic factors and the overwhelmed wearable research center of innovation. Ordered to make queries are used to study in seven information centers and sports car wearable innovation factors. This article was banned because they do not measure the program members on the sensor zero and the motor or motor factors or the application of an innovative set. Thirty-three incorporated into the collection of the full text of the survey carried out to identify members' dynamic development through observation and a slice of wearable progress in the game. Inertial sensors, the sensor and the flexible, attractive and precise speed field sensors are used in the game with more than 15 measured motion gadgets. The use of wearable innovation, the potential of these innovative practices, and the impact of competitors' training methods are still in the exploratory stage.  相似文献   
9.
The positive effects of a lithiophilic substrate on the electrochemical performance of lithium metal anodes are confirmed in several reports, while the understanding of lithiophilic substrate-guided lithium metal nucleation and growth behavior is still insufficient. In this study, the effect of a lithiophilic surface on lithium metal nucleation and growth behaviors is investigated using a large-area Ti3C2Tx MXene substrate with a large number of oxygen and fluorine dual heteroatoms. The use of the MXene substrate results in a high lithium-ion concentration as well as the formation of uniform solid–electrolyte-interface (SEI) layers on the lithiophilic surface. The solid–solid interface (MXene-SEI layer) significantly affects the surface tension of the deposited lithium metal nuclei as well as the nucleation overpotential, resulting in the formation of uniformly dispersed lithium nanoparticles ( ≈ 10–20 nm in diameter) over the entire MXene surface. The primary lithium nanoparticles preferentially coalesce and agglomerate into larger secondary particles while retaining their primary particle shapes. Subsequently, they form close-packed structures, resulting in a dense metal layer composed of particle-by-particle microstructures. This distinctive lithium metal deposition behavior leads to highly reversible cycling performance with high Columbic efficiencies >  99.0% and long cycle lives of over 1000 cycles.  相似文献   
10.
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