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   2269篇
  免费   122篇
  国内免费   3篇
电工技术   29篇
综合类   11篇
化学工业   423篇
金属工艺   51篇
机械仪表   33篇
建筑科学   204篇
矿业工程   7篇
能源动力   71篇
轻工业   204篇
水利工程   26篇
石油天然气   13篇
无线电   183篇
一般工业技术   390篇
冶金工业   215篇
原子能技术   5篇
自动化技术   529篇
  2024年   9篇
  2023年   31篇
  2022年   45篇
  2021年   68篇
  2020年   53篇
  2019年   70篇
  2018年   76篇
  2017年   63篇
  2016年   93篇
  2015年   74篇
  2014年   107篇
  2013年   171篇
  2012年   127篇
  2011年   176篇
  2010年   148篇
  2009年   101篇
  2008年   131篇
  2007年   113篇
  2006年   120篇
  2005年   101篇
  2004年   74篇
  2003年   79篇
  2002年   55篇
  2001年   43篇
  2000年   33篇
  1999年   28篇
  1998年   27篇
  1997年   15篇
  1996年   30篇
  1995年   18篇
  1994年   14篇
  1993年   11篇
  1992年   12篇
  1991年   12篇
  1990年   8篇
  1989年   13篇
  1988年   10篇
  1987年   4篇
  1986年   4篇
  1985年   4篇
  1984年   3篇
  1983年   3篇
  1982年   3篇
  1980年   5篇
  1978年   3篇
  1977年   1篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
排序方式: 共有2394条查询结果,搜索用时 58 毫秒
11.
A new target station providing Fourier transform infrared (FT-IR) spectroscopy and residual gas analysis (RGA) for in situ observation of ion-induced changes in polymers has been installed at the GSI Helmholtz Centre for Heavy Ion Research. The installations as well as first in situ measurements at room temperature are presented here. A foil of polyimide Kapton HN(?) was irradiated with 1.1 GeV Au ions. During irradiation several in situ FT-IR spectra were recorded. Simultaneously outgassing degradation products were detected with the RGA. In the IR spectra nearly all bands decrease due to the degradation of the molecular structure. In the region from 3000 to 2700 cm(-1) vibration bands of saturated hydrocarbons not reported in literature so far became visible. The outgassing experiments show a mixture of C(2)H(4), CO, and N(2) as the main outgassing components of polyimide. The ability to combine both analytical methods and the opportunity to measure a whole fluence series within a single experiment show the efficiency of the new setup.  相似文献   
12.
This study compared the antioxidative activity of green tea catechin (GTC) extract with that of rosemary extract in canola oil, pork lard, and chicken fat. The GTC extract was obtained from jasmine and longjing green teas and mainly consisted of four epicatechin isomers including (−)epigallocatechin gallate (EGCG), (−)epigallocatechin (EGC), (−)epicatechin (EC), and (−)epicatechin gallate (ECG). The oxidation was conducted at 100 ± 2°C by monitoring oxygen uptake. The oxygen consumption test demonstrated that GTC extract was much more effective than the rosemary extract against lipid oxidation in canola oil, pork lard, and chicken fat under the conditions of the present study. Together with our previous study which showed that GTC extract was more protective than butylated hydroxytoluene as an antioxidant, these results suggest that GTC as a mixture of EGCG, EGC, EC, and ECG may serve as an antioxidant in processed foods.  相似文献   
13.
14.
叶锦添 《风景园林》2009,(1):118-123
2008年11月15日,北京798的尤伦斯当代艺术中心开始呈献一场名为"迪奥与中国艺术家"的大型展览,此次展览是两块大陆之间与两种不同表达方式——当代艺术与时尚之间的对话,叶锦添、张大力、张洹、马岩松等20名中国艺术家应邀彰显创意,以其特有方式诠释迪奥(Dior)内涵,再现传统艺术与奢华时尚的完美结合。叶锦添先生的"水竹园"极富中国庭院的神韵,将众多中国当代艺术品与迪奥历年经典服装完美协调地呈现在展馆中,本刊特邀其撰文阐述创作理念,以飨读者。  相似文献   
15.
British planning is in the midst of a period of turbulence and is undergoing, many consider, an attempt by government to transform the system and the way it is operated along neoliberal lines. This may therefore be an opportune moment to encourage greater questioning about the state of UK planning. In an effort to stimulate some reflection on the contribution that academia has made in recent times the authors conducted a preliminary review of UK planning research output since 1997. The review sought to gauge the level of left-critical engagement within the literature and the results are discussed below as one small step towards raising wider questions about how to uncover the bases for a more progressive planning.  相似文献   
16.
Koshy L  Jones T  BéruBé K 《Water research》2008,42(8-9):2177-2183
The issue of domestic waste is recognised as one of the most serious environmental problems facing the nation. With the UK producing 35 million tonnes of municipal solid waste per annum, an understanding of the ranges of toxicity of landfill emissions is crucial to determine the degree of concern we should have about the potential effects these waste sites could have upon nearby populations and the surrounding environment. The aim of this study was to evaluate the bioreactivity of landfill leachates in terms of their capacity to damage ROS-sensitive bacteriophage plasmid DNA and induce toxicity in a commercial photobacterium toxicity assay, based on the light emission of Vibrio fischeri bacteria (ROTAS). The bacterial assay revealed widespread biostimulation and a hormesis response in the bacteria, with alpha-, beta- and gamma-response curves observed following exposure to the different landfill leachates. Different biological mechanisms lead to variations in bioreactivity, as seen in the plasmid DNA scission and ROTAS assays.  相似文献   
17.
正几个世纪以来,不同的地理环境一直都采用这类封闭的庭院形式——每一次都根据当地气候、风俗习惯和建筑实践进行改造。作为一种在建筑物内捕捉户外景观的手段,庭院由建筑内部结构决定。流畅的庭院不但提供内外部隐私保护,而且也不断地向外延伸,积极融入周边景观。该住宅遵守严格的分区指导方针,同时通过在屋顶上扩建自然植物区系与景观融合。坐落在橄榄树林、松树和葡萄园内,该住宅充分利用坡地,从而获得可持续的拓展和种植  相似文献   
18.
19.
This article explores the historical context, process and result of introducing and implementing ‘new’ town planning in early post‐war Taiwan. The two so‐called ‘garden cities’ are examined: Jhong‐Sing New Village and Yonghe City, both of which were formulated in the mid‐1950s by the same group of local planners. It reveals that the assumed necessity of importing Western planning paradigms arose from the abrupt escalation of urban concentration caused by the late 1940s mass migrations from China. To cope with this unprecedented population growth, planning profession was swiftly established. The novice planners, in search of a reference for developing ‘new’ towns to decentralise excessive urbanisation, modelled their ‘new’ town planning on English suburban morphology. In the absence of an input of external expertise, the planners appeared to mistake aesthetic order and pastoral imagery of low‐density residential development in England as practically viable solutions to the pressing urban problems in Taiwan. In a false hope that adopting Western ideas and practices would quickly lead the island to a better world, Taiwan initiated the importation of planning paradigms. This planning transfer not only evidently manifests a mode of ‘borrowing’ in post‐colonial countries in international diffusion but also re‐articulates the disseminating nature of modern planning and the existence of one‐direction flows characterising the global dynamics of diffusion in the twentieth century.  相似文献   
20.
Recent advancements in the domain of modeling physical processes offer opportunities to use equation based modeling environments, such as Modelica, for the simulation of building heating, ventilation, and air-conditioning (HVAC) systems. The current work demonstrates Modelica capabilities in a case study of real building solar thermal system simulation. The simulated system is part of an innovative ENERGYbase building, designed according to the so called Passivhaus standard. Model calibration and validation procedure is developed to include optimization based parametric adjustments of component models using the monitoring data during a single week. The calibrated system adequately reproduces half a year of real system operation. Future work will concentrate on application of the developed calibration and validation methodology in the whole year overall building energy simulation.  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