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   1434篇
  免费   113篇
  国内免费   62篇
电工技术   92篇
技术理论   1篇
综合类   91篇
化学工业   190篇
金属工艺   63篇
机械仪表   83篇
建筑科学   137篇
矿业工程   54篇
能源动力   52篇
轻工业   107篇
水利工程   29篇
石油天然气   148篇
武器工业   14篇
无线电   138篇
一般工业技术   157篇
冶金工业   73篇
原子能技术   26篇
自动化技术   154篇
  2024年   4篇
  2023年   20篇
  2022年   41篇
  2021年   46篇
  2020年   34篇
  2019年   34篇
  2018年   32篇
  2017年   41篇
  2016年   40篇
  2015年   70篇
  2014年   64篇
  2013年   85篇
  2012年   119篇
  2011年   114篇
  2010年   71篇
  2009年   64篇
  2008年   77篇
  2007年   94篇
  2006年   67篇
  2005年   56篇
  2004年   56篇
  2003年   61篇
  2002年   40篇
  2001年   34篇
  2000年   36篇
  1999年   51篇
  1998年   25篇
  1997年   19篇
  1996年   20篇
  1995年   31篇
  1994年   22篇
  1993年   14篇
  1992年   3篇
  1991年   7篇
  1990年   7篇
  1989年   4篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1981年   1篇
排序方式: 共有1609条查询结果,搜索用时 125 毫秒
1.
Journal of Inorganic and Organometallic Polymers and Materials - Due to their excellent properties, polymides (PIs) result promising as high-performance materials in different technological fields....  相似文献   
2.
Food Science and Biotechnology - The anti-inflammatory effects of mung bean protein hydrolysate (MBPH) on the lipopolysaccharide (LPS)-induced macrophages were investigated herein. MBPH was shown...  相似文献   
3.
Diao  Wenyu  Xu  Jiayue  Rao  Xi  Zhang  Yongping 《Catalysis Letters》2022,152(4):1029-1039
Catalysis Letters - It is crucial to explore a facile synthesis of rutile TiO2 nanorods anchored at carbon cloth at low temperature for applicable air purifier. Herein, antler-like TiO2 rectangular...  相似文献   
4.
This paper aims to find a reliable, collision-free path in a dynamic environment for highly maneuverable unmanned combat air vehicles (UCAVs). Given the real-time nature of the operational scenario, quick and adaptable reactions of UCAVs are necessary for updates in situational awareness. Therefore, we propose a three dimensional (3D) path planning approach based on the situational space to provide the tactical requirements of UCAVs for tracking targets and avoiding collisions. First, to ensure reliable nonlinear measurements, the interacting multiple model (IMM) algorithm based on a cubature Kalman filter (CKF) is chosen for the tracking and prediction algorithm. A constraint reference frame combining the kinematic model of constant acceleration (CA) is developed to solve the problem of arrival point generation. Second, by analyzing the relative motion between the UCAV and the moving objects, we define the situation space and give the corresponding calculation method. In tracking the moving target, the guidance vector contains the fusion information of displacement and velocity. At the same time, taking advantage of the one-step situation space as the judgment of the threat, we further plan the collision avoidance strategy. Third, as the safety in a practically reachable trajectory of the UCAV possesses the absolute priority, the collision avoidance acceleration accounts for this dominant factor in path planning. Simulations and experimental results prove that the proposed approach can plan a smooth and flyable path in 0.008 s under the premise of soft-landing target tracking.  相似文献   
5.
6.
在酸性体系中采用阴极扫描伏安和计时电流等电化学测试方法,研究添加十二烷基硫酸钠(SDS)对铜电沉积过程的影响机理。结果表明:SDS的添加使沉积电位正移,降低了阴极极化。SDS浓度低于临界胶束浓度1g/L时,铜的成核弛豫时间延长,形核速率降低。SDS浓度高于临界胶束浓度时,形成SDS球状胶束,铜的成核弛豫时间减少,形核速率加快。铜晶核形成过程符合Scharitker?Hill 三维成核/生长机制,当SDS为1g/L时,在-0.2V的低过电位区,铜结晶按渐进成核方式进行,在-0.23--0.28V的高过电位区,铜结晶按瞬时成核方式进行。而当SDS为0.5g/L时,铜在-0.2V--0.25V的低电位区和在-0.28V的高电位区均符合渐进成核。  相似文献   
7.
8.
Because of its ability to change optical absorption dynamically by applied electric field, nickel oxide (NiO) is a promising anodic material in smart windows, which can improve energy conversion efficiency in construction buildings. Although many works have achieved high electrochromic performance with different method. The underlying mechanism is still not fully investigated. In this article, we prepared the NiO films with large specific surface area and high stability by electron beam evaporation. X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to figure out the surface morphology and composition of as-deposited films. Afterwards, the electrochemical properties and optical performance of the prepared NiO films were investigated. On this basis, the origin of surface charge was fully analyzed by cyclic voltammetry and diffusion coefficient test. These experimental and theoretical results firmly confirm that both the surface reaction and capacitive effect bring about the excellent EC performance in NiO films. These results not only provide clear evidence about electrochemical kinetics in NiO films, but also offer some useful guidelines for the design of EC materials with higher performance and longer stability.  相似文献   
9.

Recently, deep learning, especially convolutional neural networks, has achieved the remarkable results in natural image classification and segmentation. At the same time, in the field of medical image segmentation, researchers use deep learning techniques for tasks such as tumor segmentation, cell segmentation, and organ segmentation. Automatic tumor segmentation plays an important role in radiotherapy and clinical practice and is the basis for the implementation of follow-up treatment programs. This paper reviews the tumor segmentation methods based on deep learning in recent years. We first introduce the common medical image types and the evaluation criteria of segmentation results in tumor segmentation. Then, we review the tumor segmentation methods based on deep learning from technique view and tumor view, respectively. The technique view reviews the researches from the architecture of the deep learning and the tumor view reviews from the type of tumors.

  相似文献   
10.
钢筋砼套迭梁力学性能的试验研究及计算   总被引:1,自引:0,他引:1       下载免费PDF全文
本文通过60根试验梁研究了一种新型的截面梁——套迭梁。这是一种可用钢筋砼梁本身的一部分做为模板而最终形成的整浇钢筋砼梁。这样可以不用模板即能进行浇注砼。试验研究了构件的受力特性并提出了按规范进行设计计算时的原则。  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