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   1380篇
  免费   144篇
  国内免费   1篇
电工技术   21篇
综合类   6篇
化学工业   396篇
金属工艺   33篇
机械仪表   18篇
建筑科学   69篇
矿业工程   7篇
能源动力   42篇
轻工业   159篇
水利工程   8篇
石油天然气   2篇
无线电   133篇
一般工业技术   234篇
冶金工业   145篇
原子能技术   9篇
自动化技术   243篇
  2023年   35篇
  2022年   62篇
  2021年   79篇
  2020年   54篇
  2019年   69篇
  2018年   74篇
  2017年   70篇
  2016年   74篇
  2015年   56篇
  2014年   71篇
  2013年   77篇
  2012年   67篇
  2011年   102篇
  2010年   40篇
  2009年   49篇
  2008年   51篇
  2007年   56篇
  2006年   41篇
  2005年   17篇
  2004年   18篇
  2003年   15篇
  2002年   11篇
  2001年   18篇
  2000年   14篇
  1999年   15篇
  1998年   56篇
  1997年   26篇
  1996年   19篇
  1995年   12篇
  1994年   14篇
  1993年   14篇
  1992年   6篇
  1991年   8篇
  1990年   9篇
  1989年   7篇
  1987年   6篇
  1986年   5篇
  1985年   8篇
  1984年   6篇
  1983年   5篇
  1982年   6篇
  1980年   5篇
  1979年   4篇
  1977年   5篇
  1976年   6篇
  1975年   4篇
  1973年   5篇
  1969年   7篇
  1968年   4篇
  1940年   4篇
排序方式: 共有1525条查询结果,搜索用时 15 毫秒
51.
Datenschutz und Datensicherheit - DuD - Die öffentliche Sicherheit zählt zu den wichtigsten Aufgaben der Innenpolitik. Dazu gehören der Schutz der Bürgerinnen und Bürger...  相似文献   
52.
In this paper we describe our participation in the 2017 edition of the Multi-Agent Programming Contest as team ‘lampe’. Our strategy was implemented in C++; it uses a centralised organisation of agents and evaluates different strategies based on an internal simulation of the future game state. Strategies are generated using handwritten heuristics in a randomised fashion, also relying on the internal simulation.  相似文献   
53.
54.
The primary goal of optogenetics is the light-controlled noninvasive and specific manipulation of various cellular processes. Herein, we present a hybrid strategy for targeted protein engineering combining computational techniques with electrophysiological and UV/visible spectroscopic experiments. We validated our concept for channelrhodopsin-2 and applied it to modify the less-well-studied vertebrate opsin melanopsin. Melanopsin is a promising optogenetic tool that functions as a selective molecular light switch for G protein-coupled receptor pathways. Thus, we constructed a model of the melanopsin Gq protein complex and predicted an absorption maximum shift of the Y211F variant. This variant displays a narrow blue-shifted action spectrum and twofold faster deactivation kinetics compared to wild-type melanopsin on G protein-coupled inward rectifying K+ (GIRK) channels in HEK293 cells. Furthermore, we verified the in vivo activity and optogenetic potential for the variant in mice. Thus, we propose that our developed concept will be generally applicable to designing optogenetic tools.  相似文献   
55.
56.
57.
58.
Few studies have compared individual variability of an intravenous glucose tolerance test (ivGTT) obtained daily in young cattle. The objective of this study was to evaluate the repeatability of glucose traits and insulin responses derived from ivGTT during 3 consecutive days in Holstein-Friesian cattle (bulls: n = 4, steers: n = 3, heifers: n = 3). Blood collections were performed from min 0 (basal concentrations) to min 63 (last measurement). Additional estimates included maximal concentration for glucose and insulin, glucose half-life time (GHLT), and glucose and insulin area under the curve. Glucose traits showed higher repeatability when compared with insulin responses. On average, the glucose trait and insulin response with the lowest coefficient of variation was GHLT (0.7%) and insulin area under the curve (21.3%), respectively. In addition, a general linear model with repeated measures was used to test for significant differences in glucose and insulin concentrations over time at different trial days. Both glucose and insulin concentrations were influenced by time point but not by trial day or time point × trial day. The results from this study showed that individual insulin responses were more variable than glucose traits. The high repeatability of GHLT evidenced the strict regulatory glucose disposal mechanisms occurring in young Holstein-Friesian cattle, whereas insulin responses showed high variability despite controlled management and nutritional practices.  相似文献   
59.
Forschung im Ingenieurwesen - Schneckengetriebe finden sich in verschiedenen Anwendungen als Stell- und Leistungsgetriebe. Aufgrund der Realisierbarkeit einer hohen Übersetzung bei kleinem...  相似文献   
60.
Solid solution-strengthened ductile iron (DI) exhibits outstanding mechanical properties due to the high silicon content. The strengthening by silicon addition is limited since additions above 4.3?wt-% lead to embrittlement. For a further improvement of mechanical properties, other alloying elements need to be considered. In the present work, the effect of various copper additions on the microstructure and the mechanical properties of solid solution-strengthened DI were investigated. The results show that no appreciable strengthening can be achieved by copper addition without the formation of pearlite in the matrix. The pearlite content increases considerably for Cu-additions above 0.23?wt-% and is independent of the cooling rate for the cooling conditions analysed.  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