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   1075篇
  免费   69篇
  国内免费   6篇
电工技术   11篇
综合类   6篇
化学工业   328篇
金属工艺   18篇
机械仪表   14篇
建筑科学   52篇
矿业工程   1篇
能源动力   46篇
轻工业   162篇
水利工程   12篇
石油天然气   8篇
无线电   139篇
一般工业技术   163篇
冶金工业   50篇
原子能技术   3篇
自动化技术   137篇
  2024年   2篇
  2023年   39篇
  2022年   49篇
  2021年   127篇
  2020年   59篇
  2019年   55篇
  2018年   72篇
  2017年   49篇
  2016年   114篇
  2015年   38篇
  2014年   47篇
  2013年   75篇
  2012年   61篇
  2011年   66篇
  2010年   39篇
  2009年   36篇
  2008年   36篇
  2007年   29篇
  2006年   23篇
  2005年   16篇
  2004年   12篇
  2003年   7篇
  2002年   12篇
  2001年   9篇
  2000年   6篇
  1999年   2篇
  1998年   11篇
  1997年   6篇
  1996年   10篇
  1995年   5篇
  1994年   3篇
  1993年   3篇
  1992年   2篇
  1991年   2篇
  1990年   3篇
  1989年   1篇
  1986年   3篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1981年   5篇
  1980年   5篇
  1978年   1篇
  1977年   2篇
  1976年   2篇
  1975年   1篇
  1958年   2篇
排序方式: 共有1150条查询结果,搜索用时 15 毫秒
1.
A new strategy for the selective coating of tin sulfide (SnS) on the surface of moth‐eye patterned (MEP) conducting polymer film is studied by considering the optical properties of the antireflective moth‐eye pattern and flexibility of polymer films. The semiconductor SnS is selectively coated on the surface of MEP microdomes of poly(3,4‐ethylenedioxythiophene) poly(styrene‐sulfonate) (PEDOT:PSS) film. The SnS coated MEP film is obtained by using pore selectively SnS thin layer functionalized polystyrene honeycomb‐patterned porous (HCP) film as a template. Aqueous PEDOT:PSS solution is poured on the SnS functionalized HCP films and detached for the fabrication of SnS coated MEP films. The films show a satisfactory photo‐responsive property under solar stimulated light illumination due to the antireflective MEP structure of PEDOT film and homogenous SnS coating on the surface of the conducting polymer.  相似文献   
2.
Vu  Hoa T.  Nguyen  Manh B.  Vu  Tan M.  Le  Giang H.  Pham  Trang T. T.  Nguyen  Trinh Duy  Vu  Tuan A. 《Topics in Catalysis》2020,63(11-14):1046-1055
Topics in Catalysis - Nano Fe-BTC/graphene oxide (GO) composites were successfully synthesized by hydrothermal treatment with a microwave-assisted method. Samples were characterized by X-ray...  相似文献   
3.
Wireless Personal Communications - In the formulating of power control for wireless networks, the radio channel is commonly formulated using static models of optimization or game theory. In these...  相似文献   
4.
Ethanol steam reforming (ESR) is one of the potential processes to convert ethanol into valuable products. Hydrogen produced from ESR is considered as green energy for the future and can be an excellent alternative to fossil fuels with the aim of mitigating the greenhouse gas effect. The ESR process has been well studied, using transition metals as catalysts coupled with both acidic and basic oxides as supports. Among various reported transition metals, Ni is an inexpensive material with activity comparable to that of noble metals, showing promising ethanol conversion and hydrogen yields. Additionally, different promoters and supports were utilized to enhance the hydrogen yield and the catalyst stability. This review summarizes and discusses the influences of the supports and promoters of Ni-based catalysts on the ESR process.  相似文献   
5.
FeO-doped TiO2 nanoparticle photocatalysts were immobilized onto the surface of fibrous activated carbon (ACF) via a sol-gel process. As an adsorbent and photocatalyst, FeO-TiO2 on immobilized ACFs (FeO-TiO2/ACF) greatly improved the photocatalysis rate of hydrogen production as compared with pure TiO2 and ACF-TiO2 under UV irradiation and visible light. The addition of ACFs surface significantly reduced the photogenerated pairs of electrons-hole recombination, thereby promoting the photocatalysis action of doped photo-metal oxides of FeO-TiO2. Co-doping of FeO onto the lattice of the TiO2 approach can improve the absorption activity of visible light through photo-metal oxide of TiO2 and further enhance hydrogen production under visible light. The photocatalytic fabrics (FeO-TiO2/ACF) were effortlessly split out from the experimental solution for re-utilization and exhibited high stability even after five complete regeneration cycles.  相似文献   
6.
This paper presents a new 1-D non-local damage-plasticity deformation model for ductile materials. It uses the thermodynamic framework described in Houlsby and Puzrin (2000) and holds, nevertheless, some similarities with Lemaitre’s (1971) approach. A 1D finite element (FE) model of a bar fixed at one end and loaded in tension at the other end is introduced. This simple model demonstrates how the approach can be implemented within the finite element framework, and that it is capable of capturing both the pre-peak hardening and post-peak softening (generally responsible for models instability) due to damage-induced stiffness and strength reduction characteristic of ductile materials. It is also shown that the approach has further advantages of achieving some degree of mesh independence, and of being able to capture deformation size effects. Finally, it is illustrated how the model permits the calculation of essential work of rupture (EWR), i.e. the specific energy per unit cross-sectional area that is needed to cause tensile failure of a specimen.  相似文献   
7.
PMMA/PBA乳胶IPN阻尼材料的研究   总被引:3,自引:0,他引:3  
用乳液聚合方法合成了一系列的互穿聚合物网络,其中包括:PMMA/PBA和P(MMA-co-PMA)/PBA乳胶互穿聚合物网络(LIPN),PMMA/PBA乳胶双向互穿聚合物网络(LBIPN)以及PMMA/PBA界面交联互穿聚合物网络(ICLIPN)。动态力学谱和拉伸试验结果表明:(1)PMMA/PBA互穿聚合物网络的两组分相容性和阻尼性能可通过MMA和PMA共聚来改善;(2)双向互穿技术是一种行之  相似文献   
8.
Polyelectrolyte complex based on chitosan and acrylic acid monomer by photoinitiated free‐radical polymerization in the absence of crosslinker showed a large transition in swelling in response to changes in pH of surrounding medium. Their ability to swell arises from polyelectrolyte interactions and molecular structure of the complex. The main properties of interest that related to the molecular structure, swelling volumes, glass transition temperature, and elastic modulus of the complex were investigated. The effect of water content, the only variable in the sample component, played an important role in molecular structure of the complex and as a consequence, the extent of intermolecular linkage, especially amide bonds which in turn governed the degree of swelling of the polyelectrolyte complex in this study. The decreased degree of swelling and higher temperature shift of glass transition temperature was found with increased water content, whereas increased modulus of elasticity of dry complex was found in lower water content of synthesis component. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1025–1035, 2002  相似文献   
9.
A statistical analysis of compositional data based on the Aitchison geometry of the simplex requires an appropriate basis for representing the data. A simple and intuitive way of building such a basis employs a sequential binary partition of the compositional vector. The partition, together with some statistical summaries of the coordinates, or balances, can be represented in a dendrogram-type graph. In this paper we introduce an implementation of this methodology inside CoDaPack, which is freeware. An example with real data illustrates the use of the Balance-Dendrogram routine.  相似文献   
10.
Knowledge and Information Systems - With the advance of information technology, many fields have begun using data clustering to reveal data structures and obtain useful information. Most of the...  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