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   343篇
  免费   25篇
电工技术   2篇
综合类   1篇
化学工业   120篇
金属工艺   4篇
机械仪表   7篇
建筑科学   22篇
能源动力   14篇
轻工业   49篇
水利工程   2篇
无线电   14篇
一般工业技术   51篇
冶金工业   25篇
原子能技术   1篇
自动化技术   56篇
  2023年   6篇
  2022年   15篇
  2021年   12篇
  2020年   16篇
  2019年   9篇
  2018年   10篇
  2017年   11篇
  2016年   19篇
  2015年   18篇
  2014年   18篇
  2013年   23篇
  2012年   15篇
  2011年   18篇
  2010年   30篇
  2009年   17篇
  2008年   21篇
  2007年   23篇
  2006年   11篇
  2005年   8篇
  2004年   11篇
  2003年   4篇
  2002年   8篇
  2001年   2篇
  2000年   4篇
  1999年   8篇
  1998年   5篇
  1997年   6篇
  1996年   4篇
  1994年   2篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1989年   3篇
  1988年   1篇
  1985年   2篇
  1981年   1篇
  1978年   1篇
  1972年   1篇
排序方式: 共有368条查询结果,搜索用时 15 毫秒
81.
This article presents empirical evidence challenging the received wisdom that a nonword-reading deficit is a characteristic trait of disabled readers. On the basis of 2 large-scale empirical studies using the reading-level match design, we argue that a nonword-reading deficit is the consequence of normal developmental differences in word-specific knowledge between disabled readers and younger normal readers (both groups being matched on real-word reading). The first study shows that the nonword-reading deficit varies as a function of age and reading level and that this deficit is not typical for disabled readers. The second study demonstrates that a nonword-reading deficit crucially depends on the sensitivity of the matching word reading task to detect age-related differences in word-specific knowledge between disabled and normal readers. We clarify how these findings can be interpreted within the current framework of the phonological deficit hypothesis and discuss implications for theories of reading development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
82.
We present Stratosphere, an open-source software stack for parallel data analysis. Stratosphere brings together a unique set of features that allow the expressive, easy, and efficient programming of analytical applications at very large scale. Stratosphere’s features include “in situ” data processing, a declarative query language, treatment of user-defined functions as first-class citizens, automatic program parallelization and optimization, support for iterative programs, and a scalable and efficient execution engine. Stratosphere covers a variety of “Big Data” use cases, such as data warehousing, information extraction and integration, data cleansing, graph analysis, and statistical analysis applications. In this paper, we present the overall system architecture design decisions, introduce Stratosphere through example queries, and then dive into the internal workings of the system’s components that relate to extensibility, programming model, optimization, and query execution. We experimentally compare Stratosphere against popular open-source alternatives, and we conclude with a research outlook for the next years.  相似文献   
83.
Neck injuries sustained in low severity vehicle crashes are of worldwide concern and the risk is higher for females than for males. The objective of the study was to provide guidance on how to evaluate protective performance of vehicle seat designs aiming to reduce the incidence of neck injuries for female and male occupants. The objective was achieved by reviewing injury risk, establishing anthropometric data of an average female, performing dynamic volunteer tests comprising females and males, and developing a finite element model, EvaRID, of an average female. With respect to injury criteria, it was concluded based on the tests that using NIC (with a lower threshold value) and Nkm (with reduced intercept values) for females would be a suitable starting point. Virtual impact simulations with seats showed that differences were found in the response of the BioRID II and EvaRID models, for certain seats.  相似文献   
84.
The production of Aspergillus niger glucose oxidase (GOX) and native amylase by the recombinant M. circinelloides KFA199 strain under conditions of dimorphic growth was investigated. The recombinant KFA199 strain was compared to its parental ATCC 1216b strain and a wild‐type CBS 232.29 strain under similar morphology‐controlled conditions. Cultivation in Vogel's medium supplemented with ergosterol/Tween‐80 and sparged with nitrogen gas was most suitable for yeast‐like biomass production under anaerobic conditions. Anaerobic growth was characterized by high levels of ethanol formation and linear growth rates of 0.24–0.05/h, indicating metabolic stress. Subsequent to anaerobic growth, cultures were shifted to aerobic conditions to induce aerobic mycelial growth. GOX produced by the recombinant KFA199 after the shift to aerobic conditions was poorly secreted and accumulated intracellularly to 0.56 U/mlculture. Amylase production by the KFA199, ATCC12b and CBS 232.29 strains was determined during growth on starch after the shift to aerobic culture. Growth‐associated amylase production by the ATCC 1216b (0.63 U/mlculture) and wild‐type CBS 232.29 (0.33 U/mlculture) strains was substantially higher than by the recombinant KFA199 strain (0.07 U/mlculture), which may be related to the leucine auxotrophy of the transformation host, or genetic changes induced during transformation of the KFA199 strain. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
85.
86.
大连足球场     
这一体育场的设计灵感来源于中国古代蹴鞠的色彩层次和叠加的构造。设计将观众的集体精神、建筑的公共领域和城市内涵交织在一起。主体育场将观众席、广播电视中心、管理区、贵宾休息室、运动员设施和公共大厅安置在一个分层次的空间中,这一空间延伸到地表层,在双层停车设施上部提供户外的公共空间。  相似文献   
87.
该大楼有20层,包含55个公寓,在楼中可以眺望啥德逊河、东河和曼哈顿的天际线。 该大楼有一个戏剧性、极富装饰性的立面,灵感来自Tribeca的19世纪的铸铁建筑和当代时尚。闪闪发光的黑色金属横带将包装的墙面扭曲,划分了阳台、平台和遮阳篷的位置,同时体现了立面的框架感。  相似文献   
88.
According to the Intergovernmental Panel on Climate Change the buildings sector has the largest mitigation potential for CO2 emissions. Especially in office buildings, where internal heat loads and a relatively high occupant density occur at the same time with solar heat gains, overheating has become a common problem. In Europe the adaptive thermal comfort model according to EN 15251 provides a method to evaluate thermal comfort in naturally ventilated buildings. However, especially in the context of the climate change and the occurrence of heat waves within the last decade, the question arises, how thermal comfort can be maintained without additional cooling, especially in warm climates. In this paper a parametric study for a typical cellular naturally ventilated office room has been conducted, using the building simulation software EnergyPlus. It is based on the Mediterranean climate of Athens, Greece. Adaptive thermal comfort is evaluated according to EN 15251. Variations refer to different building design priorities, and they consider the variability of occupant behaviour and internal heat loads by using an ideal and worst case scenario. The influence of heat waves is considered by comparing measured temperatures for an average and an exceptionally hot year within the last decade. Since the use of building controls for shading affects thermal as well as visual comfort, daylighting and view are evaluated as well. Conclusions are drawn regarding the influence and interaction of building design, occupants and heat waves on comfort and greenhouse gas emissions in naturally ventilated offices, and related optimisation potential.  相似文献   
89.
90.
Real-time detection of oligomers in secondary organic aerosols has been carried out with an aerosol time-of-flight mass spectrometer sampling particles generated in a smog chamber. The photooxidation products of 1,3,5-trimethylbenzene and NOx were studied over a range of initial 1,3,5-trimethylbenzene concentrations (137-1180 ppb), while keeping the 1,3,5-trimethylbenzene to NOx ratio nearly constant. The photooxidation products of a mixture of alpha-pinene (initial concentration 191 ppb), 1,3,5-trimethylbenzene (60 ppb), and NOx were also investigated. In both systems, ions were observed in the single-particle mass spectra up to 750 Da; the species observed differed in the two systems. These high-mass ions occur with characteristic spacing of 14 and 16 Da, indicative of oligomeric species. The results obtained agree well with off-line (matrix-assisted) laser desorption/ionization mass spectrometry results. The real-time capabilities of the aerosol time-of-flight mass spectrometer make it possible to investigate the temporal development of the oligomers with 5-min time resolution and also demonstrate that there are certain ions within the oligomer population that occur in nearly all of the particles and with relatively high signal intensity, suggesting that these ions have higher stability or that the species are formed preferentially.  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