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   11756篇
  免费   463篇
  国内免费   123篇
电工技术   278篇
综合类   200篇
化学工业   2369篇
金属工艺   401篇
机械仪表   426篇
建筑科学   405篇
矿业工程   107篇
能源动力   461篇
轻工业   739篇
水利工程   125篇
石油天然气   167篇
武器工业   16篇
无线电   1310篇
一般工业技术   2622篇
冶金工业   1289篇
原子能技术   121篇
自动化技术   1306篇
  2023年   111篇
  2022年   219篇
  2021年   311篇
  2020年   253篇
  2019年   217篇
  2018年   348篇
  2017年   264篇
  2016年   294篇
  2015年   254篇
  2014年   342篇
  2013年   734篇
  2012年   472篇
  2011年   575篇
  2010年   494篇
  2009年   465篇
  2008年   461篇
  2007年   431篇
  2006年   375篇
  2005年   323篇
  2004年   283篇
  2003年   271篇
  2002年   230篇
  2001年   205篇
  2000年   237篇
  1999年   258篇
  1998年   349篇
  1997年   292篇
  1996年   263篇
  1995年   228篇
  1994年   209篇
  1993年   196篇
  1992年   173篇
  1991年   168篇
  1990年   110篇
  1989年   121篇
  1988年   122篇
  1987年   124篇
  1986年   98篇
  1985年   151篇
  1984年   139篇
  1983年   146篇
  1982年   105篇
  1981年   107篇
  1980年   96篇
  1979年   101篇
  1978年   85篇
  1977年   80篇
  1976年   84篇
  1975年   62篇
  1974年   58篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
This study presents the development and characterization of PVDF-conjugated polymer nanofiber-based systems. Five different conducting polymers (CPs) were synthesized successfully and used to create the nanofiber systems. The CPs used are polyaniline (PANI), polypyrrole (PPY), polyindole (PIN), polyanthranilic acid (PANA), and polycarbazole (PCZ). Nanofiber systems were produced utilizing the Forcespinning® technique. The nanofiber systems were developed by mechanical stretching. No electrical field or post-process poling was used in the nanofiber systems. The morphology, structure, electrochemical and piezoelectric performance was characterized. All of the nanofiber PVDF/CP systems displayed higher piezoelectric performance than the fine fiber PVDF systems. The PVDF/PPY nanofiber system displays the highest piezoelectric performance of 15.56 V. The piezoelectric performance of the PVDF/CP nanofiber systems favors potential for an attractive source of energy where highly flexible membranes could be used in power actuators, sensors and portable, and wireless devices to mention some.  相似文献   
2.
3.
Ganapati  Reddi  Samoju  Visweswara Rao  Jammu  Bhaskara Rao 《SILICON》2021,13(9):2869-2880
Silicon - This paper presents, analytical modeling of surface potential,threshold voltage and DIBL for a Dual-Metal Double-Gate Gate-All-Around (DM-DG-GAA) MOSFET considering the parabolic...  相似文献   
4.
5.
The custom design of protein–dendron amphiphilic macromolecules is at the forefront of macromolecular engineering. Macromolecules with this architecture are very interesting because of their ability to self-assemble into various biomimetic nanoscopic structures. However, to date, there are no reports on this concept due to technical challenges associated with the chemical synthesis. Towards that end, herein, a new chemical methodology for the modular synthesis of a suite of monodisperse, facially amphiphilic, protein–dendron bioconjugates is reported. Benzyl ether dendrons of different generations (G1–G4) are coupled to monodisperse cetyl ethylene glycol to form macromolecular amphiphilic activity-based probes (AABPs) with a single protein reactive functionality. Micelle-assisted protein labeling technology is utilized for site-specific conjugation of macromolecular AABPs to globular proteins to make monodisperse, facially amphiphilic, protein–dendron bioconjugates. These biohybrid conjugates have the ability to self-assemble into supramolecular protein nanoassemblies. Self-assembly is primarily mediated by strong hydrophobic interactions of the benzyl ether dendron domain. The size, surface charge, and oligomeric state of protein nanoassemblies could be systematically tuned by choosing an appropriate dendron or protein of interest. This chemical method discloses a new way to custom-make monodisperse, facially amphiphilic, protein–dendron bioconjugates.  相似文献   
6.
The cover image is based on the Research Article V2O5/RGO/Pt nanocomposite on oxytetracycline degradation and pharmaceutical effluent detoxification by Mohan, H et al., DOI: 10.1002/jctb.6238 .

  相似文献   

7.
The performance of low-to-intermediate temperature (400–800?°C) solid oxide fuel cells (SOFCs) depends on the properties of electrolyte used. SOFC performance can be enhanced by replacing electrolyte materials from conventional oxide ion (O2-) conductors with proton (H+) conductors because H+ conductors have higher ionic conductivity and theoretical electrical efficiency than O2- conductors within the target temperature range. Electrolytes based on cerate and/or zirconate have been proposed as potential H+ conductors. Cerate-based electrolytes have the highest H+ conductivity, but they are chemically and thermally unstable during redox cycles, whereas zirconate-based electrolytes exhibit the opposite properties. Thus, tailoring the properties of cerate and/or zirconate electrolytes by doping with rare-earth metals has become a main concern for many researchers to further improve the ionic conductivity and stability of electrolytes. This article provides an overview on the properties of four types of cerate and/or zirconate electrolytes including cerate-based, zirconate-based, single-doped ceratezirconate and hybrid-doped ceratezirconate. The properties of the proton electrolytes such as ionic conductivity, chemical stability and sinterability are also systematically discussed. This review further provides a summary of the performance of SOFCs operated with cerate and/or zirconate proton conductors and the actual potential of these materials as alternative electrolytes for proton-conducting SOFC application.  相似文献   
8.
The present study attempts quantitative determination of changes in the morphological surface features viz. fractal dimension, lower and upper cut off length scale through Power Spectral Density analysis prior to and after irradiation of 100 KeV Ar+ ion beam at incidence angles of 0°, 40° and 60° on ZnO thin films. All the unirradiated and irradiated samples are subjected to photoelectrochemical characterization and a correlation between photoelectrochemical performance and morphological parameters is established. Sample irradiated at 40° angle at the fluence of 5 × 1016 ions/cm2 is found to possess maximum fractal dimension of 2.72, lower and upper cut off length scale of 3.16 nm and 63.00 nm respectively. This sample exhibits maximum photocurrent density of 3.19 mA/cm2 and applied bias photon-to-current efficiency of 1.12% at 1.23 V/RHE. Hydrogen gas collected for duration of 1 h for the same sample was ~4.83 mLcm?2.  相似文献   
9.
10.
Neural Computing and Applications - We propose “Deep Autoencoders for Feature Learning in Recommender Systems,” a novel discriminative model based on the incorporation of features from...  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