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   3950篇
  免费   101篇
  国内免费   10篇
电工技术   134篇
综合类   7篇
化学工业   831篇
金属工艺   175篇
机械仪表   74篇
建筑科学   45篇
矿业工程   6篇
能源动力   115篇
轻工业   247篇
水利工程   16篇
石油天然气   2篇
无线电   450篇
一般工业技术   667篇
冶金工业   885篇
原子能技术   115篇
自动化技术   292篇
  2023年   34篇
  2022年   69篇
  2021年   107篇
  2020年   50篇
  2019年   61篇
  2018年   75篇
  2017年   60篇
  2016年   77篇
  2015年   63篇
  2014年   77篇
  2013年   186篇
  2012年   151篇
  2011年   206篇
  2010年   138篇
  2009年   161篇
  2008年   178篇
  2007年   135篇
  2006年   96篇
  2005年   96篇
  2004年   97篇
  2003年   97篇
  2002年   96篇
  2001年   66篇
  2000年   58篇
  1999年   64篇
  1998年   346篇
  1997年   187篇
  1996年   174篇
  1995年   96篇
  1994年   92篇
  1993年   97篇
  1992年   44篇
  1991年   37篇
  1990年   33篇
  1989年   44篇
  1988年   46篇
  1987年   39篇
  1986年   25篇
  1985年   31篇
  1984年   27篇
  1983年   32篇
  1982年   29篇
  1981年   31篇
  1980年   37篇
  1979年   15篇
  1978年   17篇
  1977年   20篇
  1976年   35篇
  1975年   8篇
  1973年   5篇
排序方式: 共有4061条查询结果,搜索用时 15 毫秒
61.
The penetration phenomena of liquid manganese (Mn) alloy into porous ZrO2 (8 vvt % Y2O3) coating plasma sprayed on SS400 steel substrate was studied by heating in a vacuum atmosphere. The improvement in mechanical properties of the coating by heat treatment with liquid Mn alloys was examined. Liquid Mn alloys, such as Mn-Cu, Mn-Sn, and Mn-In, rapidly penetrated the coating and formed a chemical bond between the coating and the substrate. The densification of the ZrO2 coating occurred when ZrO2 particles were sintered with liquid Mn alloys that penetrated the porous coating. The dense coating was free of porosity, and its hardness increased after heat treatment with Mn alloys, compared with assprayed ZrO2 coating. Moreover, the fracture toughness of the coating reached the same levels as those of sintered yttria-stabilized PSZ.  相似文献   
62.
To improve the reliability and mechanical durability of a flexible organic light‐emitting diode display, the entire flexible display is coated with an aluminum oxide film by atomic layer deposition (ALD). Because the step coverage of ALD is excellent, the AlOx film was deposited not only on the front and back surfaces but also on the side surfaces of the display. A high‐temperature and high‐humidity preservation test, repetitive bending tests, and a pencil hardness test were conducted on the flexible display with ALD‐AlOx coating. The display survived 500 h of a 65°C, 95% preservation test, endured a 100,000‐time repetitive bending test with a curvature radius of 4 mm, and was found to have a pencil hardness of 4H.  相似文献   
63.
Computational Visual Media - Iris folding is an art-form consisting of layered strips of paper, forming a spiral pattern behind an aperture, which can be used to make cards and gift tags. This...  相似文献   
64.
Recently, we revealed a standard pattern of a macroscopic molecular network for controlling morphogenetic processes such as the development of organs, including blast, mesoderm, heart, and hands during about sevenfold cell divisions and a standard bio-chemical clock like the circadian one (Naitoh in Artif Life Robot 13, 2008; Japan J Ind Appl Math 28(1), 2011; J Phys Conf Ser 344, 2012; Artif Life Robot 17, 2012) A network model derived logically based on experimental observations is described by a nonlinear differential equation for predicting time evolutions of six macroscopic molecular groups: three gene groups and three enzyme groups, which include promoting and suppressing factors. Here, the macroscopic model extended for also describing aging processes shows various types of cycles and reveals the physical condition for determining whether or not living beings such as humans can survive after getting ill. It is stressed that, after becoming ill, living systems with overly fast generation of information molecules such as various genes end in death, whereas relatively fast production of enzymes leads to recovery. This may also explain an essential feature underlying carcinogenic processes.  相似文献   
65.
To improve the performance of embedded processors, an effective technique is collapsing critical computation subgraphs as application-specific instruction set extensions and executing them on custom functional units. The problem with this approach is the immense cost and the long times required to design a new processor for each application. As a solution to this issue, we propose an adaptive extensible processor in which custom instructions (CIs) are generated and added after chip-fabrication. To support this feature, custom functional units are replaced by a reconfigurable matrix of functional units (FUs). A systematic quantitative approach is used for determining the appropriate structure of the reconfigurable functional unit (RFU). We also introduce an integrated framework for generating mappable CIs on the RFU. Using this architecture, performance is improved by up to 1.33, with an average improvement of 1.16, compared to a 4-issue in-order RISC processor. By partitioning the configuration memory, detecting similar/subset CIs and merging small CIs, the size of the configuration memory is reduced by 40%.  相似文献   
66.
Abstract— In order to improve the reflective contrast ratio of transflective IPS‐LCDs, a novel pixel design for a normally white reflective IPS has been proposed. In this design, the large‐inter‐electrode‐spacing layout using a novel driving method and a double‐layered electrode have effectively reduced the light leakage. By applying these two technologies, a transflective IPS‐LCD has been successfully demonstrated with a high contrast ratio (15:1) in the reflective mode and a wide‐viewing‐angle characteristic in the transmissive mode.  相似文献   
67.
We developed equipment and methods for measuring quantitatively the local Young's modulus of solids. It consists of an electrodeless langasite oscillator and line antennas, and oscillator vibrations are generated and detected contactlessly. A constant biasing force results from oscillator mass and is independent of surface roughness. The effect of material anisotropy on the measured stiffness is theoretically discussed for studying the limitation of the quantitative measurement. The microscopy has been applied to polycrystalline copper, and the measured modulus is compared to calculations based on electron-backscatter-diffraction measurements. Also, we applied it to a duplex stainless steel and an embedded silicon-carbide fiber. The results reveal textured regions, defects with high sensitivity, and even stiffness distribution in a single grain.  相似文献   
68.
Based on scientific databases adopted for designing ITER plasmas and on the advancement of fusion nuclear technology from the recent R&D program, a low wall-loading DEMO fusion reactor has been designed, where high priority has been given to the early and reliable realization of a tokamak fusion plasma over the cost performance. Since the major radius of this DEMO reactor is chosen to be 10 m, plasma ignition is achievable with a low fusion power of 0.8 GW and an operation period of 4–5 hours is available only with inductive current drive. The low ignition power makes it possible to adopt a first wall with an austenitic stainless steel, for which significant databases and operating experience exists, due to its use in the presence of neutron irradiation in fission reactors. In step with development of advanced materials, a step-wise increase of the fusion power seems to be feasible and realistic, because this DEMO reactor has the potential to produce a fusion power of 5 GW.  相似文献   
69.
Pouliquen  M.  Denoual  M.  Jorel  C.  Radu  C.  Robbes  D.  Grand  J.  Awala  H.  Mintova  S.  Harnois  M.  Sagazan  O. de  Inoue  S.  Lebrasseur  E.  Yamada  K.  Okamoto  Y.  Mita-Tixier  A.  Mita  Y. 《Microsystem Technologies》2022,28(6):1313-1319
Microsystem Technologies - We demonstrate a new operation mode of thermal gas sensor based on thermal capacity extraction with identification algorithm. The system is a silicon microstructure...  相似文献   
70.
A new kind of the Vernier mechanism that is able to control the size of linear assembly of DNA origami nanostructures is proposed. The mechanism is realized by mechanical design of DNA origami, which consists of a hollow cylinder and a rotatable shaft in it connected through the same scaffold. This nanostructure stacks with each other by the shape complementarity at its top and bottom surfaces of the cylinder, while the number of stacking is limited by twisting angle of the shaft. Experiments have shown that the size distribution of multimeric assembly of the origami depends on the twisting angle of the shaft; the average lengths of the multimer are decamer, hexamer, and tetramer for 0°, 10°, and 20° twist, respectively. In summary, it is possible to affect the number of polymerization by adjusting the precise shape and movability of a molecular structure.  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