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   236146篇
  免费   24164篇
  国内免费   13601篇
电工技术   18113篇
技术理论   10篇
综合类   18412篇
化学工业   34852篇
金属工艺   14402篇
机械仪表   16006篇
建筑科学   19204篇
矿业工程   7692篇
能源动力   7046篇
轻工业   17715篇
水利工程   5329篇
石油天然气   12439篇
武器工业   2529篇
无线电   28420篇
一般工业技术   25272篇
冶金工业   10252篇
原子能技术   2653篇
自动化技术   33565篇
  2024年   1218篇
  2023年   4046篇
  2022年   7881篇
  2021年   10793篇
  2020年   8147篇
  2019年   6459篇
  2018年   7112篇
  2017年   8181篇
  2016年   7180篇
  2015年   10515篇
  2014年   13024篇
  2013年   15381篇
  2012年   17463篇
  2011年   18531篇
  2010年   16684篇
  2009年   15771篇
  2008年   15679篇
  2007年   14676篇
  2006年   13772篇
  2005年   10916篇
  2004年   7606篇
  2003年   6588篇
  2002年   6401篇
  2001年   5625篇
  2000年   4680篇
  1999年   4149篇
  1998年   2888篇
  1997年   2390篇
  1996年   2162篇
  1995年   1852篇
  1994年   1487篇
  1993年   963篇
  1992年   781篇
  1991年   590篇
  1990年   495篇
  1989年   417篇
  1988年   282篇
  1987年   222篇
  1986年   163篇
  1985年   106篇
  1984年   83篇
  1983年   69篇
  1982年   63篇
  1981年   70篇
  1980年   73篇
  1979年   44篇
  1978年   25篇
  1976年   28篇
  1975年   18篇
  1973年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Malondialdehyde (MDA) was selected to represent a secondary by-product of lipid peroxidation during rice ageing. This study aimed to investigate the effects of MDA modification on the structural characteristics of rice protein. The results showed that as MDA concentration increased, rice protein carbonyl and disulphide groups increased, but sulphydryl content decreased. The blue shift of maximum fluorescence peak, the decrease of rice protein intrinsic fluorescence intensity and the reduction of surface hydrophobicity indicated the formation of protein aggregates caused by MDA oxidative modification. The results of molecular weight distribution and particle size distribution showed that MDA modification resulted in the formation of soluble protein aggregates, and the decrease of rice protein solubility indicated that insoluble protein aggregates were formed. Results of protein electrophoresis showed that MDA modification contributed to rice protein aggregation via non-disulphide covalent bonds. The results showed that rice protein gradually aggregated with increasing MDA concentration.  相似文献   
53.
Science China Technological Sciences - Accurate modelling of lithium ion batteries is crucial for battery management in electric vehicles. Recent studies have revealed the fractional order nature...  相似文献   
54.
徐浩  吴炜  陈浩  王子康 《电子测试》2020,(10):117-118,27
无人机技术目前的快速发展使得我们国家输电线路自身的巡检能力得到了持续的提升,基于此本文在对无人机技术给予认识的情况下,在了解了输电线路巡检过程中的使用优势之后,还总结了无人机技术在当前我国线路巡检过程中的应用路径以及应用方法;之后使用案例分析的方式分析了无人机技术在当前输电线路巡检过程中的应用方法。  相似文献   
55.
液滴撞击干燥倾斜壁面铺展实验研究   总被引:2,自引:0,他引:2       下载免费PDF全文
通过高速摄影技术及像素分析方法对液滴撞击干燥倾斜壁面进行实验研究,分析了不同倾斜角及韦伯数(We)对液滴飞溅及铺展的影响,结果表明,倾斜角的增加有利于抑制飞溅的产生;We一定时,液滴的前铺展因子随着倾斜角的增加而增加,后铺展因子随着倾斜角的增加而减小;液滴的前后初始铺展速度均大于液滴的撞击速度,且随着倾斜角的增加而减小。   相似文献   
56.
Amphotericin B (AMB) was often used in intra-articular injection administration for fungal arthritis, because it could often bring a satisfactory therapeutic efficacy and a minimum systemic toxic side effect. However, because of the multiple operations and the frequent injections, the compliance of the patients was bad. Therefore, to develop a long-term sustained-released preparation of AMB for mycotic arthritis intra-articular administration is of great significance. The purpose of present study was to develop a long-term sustained-released in situ gel of a water-insoluble drug AMB for mycotic arthritis intra-articular administration. Based on the evaluations of the in vitro properties of the formulations, the formulation containing 10% (w/w) ethanol, 15% (w/w) PG, 0.75% (w/w) HA, 5% (w/w) purified soybean oil, 0.03% (w/w) α-tocopherol, 15% (w/w) water and 55% (w/w) glyceryl monooleate was selected as a suitable intra-articular injectable in situ gel drug delivery system for water-insoluble drug AMB. Furthermore, the results of the in vivo study on rabbits showed that the selected formulation was a safe and effective long-term sustained-released intra-articular injectable AMB preparation. Therefore, the presented in situ AMB gel could reduce the frequency of the administration in the AMB treatment of fungal arthritis, and then would get a good patient compliance.  相似文献   
57.
Peer-to-Peer Networking and Applications -  相似文献   
58.
59.
60.
Semiconductor particles doped Al2O3 coatings were prepared by cathode plasma electrolytic deposition in Al(NO3)3 electrolyte dispersed with SiC micro- and nano-particles (average particle sizes of 0.5–1.7?µm and 40?nm respectively). The effects of the concentrations and particle sizes of the SiC on the microstructures and tribological performances of the composite coatings were studied. In comparison with the case of dispersing with SiC microparticles, the dispersion of SiC nanoparticles in the coatings was more uniform. When the concentration of SiC nanoparticles was 5?g/L, the surface roughness of the composite coating was reduced by 63%, compared with that of the unmodified coating. Friction results demonstrated that the addition of 5?g/L SiC nanoparticles reduced the friction coefficient from 0.60 to 0.38 and decreased the wear volume under dry friction. The current density and bath voltage were measured to analyze the effects of SiC particles on the deposition process. The results showed that the SiC particles could alter the electrical behavior of the coatings during the deposition process, weaken the bombardment of the plasma, and improve the structures of the coatings.  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