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   22222篇
  免费   2864篇
  国内免费   1496篇
电工技术   754篇
技术理论   6篇
综合类   2591篇
化学工业   987篇
金属工艺   484篇
机械仪表   775篇
建筑科学   7961篇
矿业工程   470篇
能源动力   315篇
轻工业   951篇
水利工程   725篇
石油天然气   1368篇
武器工业   117篇
无线电   1867篇
一般工业技术   1121篇
冶金工业   345篇
原子能技术   155篇
自动化技术   5590篇
  2024年   162篇
  2023年   523篇
  2022年   795篇
  2021年   873篇
  2020年   980篇
  2019年   740篇
  2018年   550篇
  2017年   592篇
  2016年   596篇
  2015年   748篇
  2014年   1515篇
  2013年   1238篇
  2012年   1520篇
  2011年   1797篇
  2010年   1475篇
  2009年   1441篇
  2008年   1508篇
  2007年   1679篇
  2006年   1439篇
  2005年   1129篇
  2004年   968篇
  2003年   783篇
  2002年   651篇
  2001年   507篇
  2000年   382篇
  1999年   333篇
  1998年   280篇
  1997年   209篇
  1996年   188篇
  1995年   180篇
  1994年   173篇
  1993年   112篇
  1992年   94篇
  1991年   65篇
  1990年   57篇
  1989年   53篇
  1988年   28篇
  1987年   23篇
  1986年   17篇
  1985年   33篇
  1984年   27篇
  1983年   19篇
  1982年   17篇
  1981年   14篇
  1980年   11篇
  1979年   11篇
  1978年   8篇
  1977年   10篇
  1975年   5篇
  1973年   4篇
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
971.
To the student of landscape, as well as to the landscape planner, designer and manager, it is important to distinguish between differing modalities in the conceptualization of landscape and seasonality. The logic of the absolute geometric space of the map and central point perspective prospect, and the chronometric time of the calendar, is qualitatively different from the liminality of place and seasonal holidays. Here it is the content that defines the seasons, not the regularities of a quantitative system of measurement. This distinction is critical when it comes to working with seasonal landscapes, because they can be defined in terms of either modality.  相似文献   
972.
Landscape and law cross-influence each other. Legal rules shape landscapes, while landscapes shape the culture from which rules emerge. In describing this interplay, landscape can seem passive, as a canvas on which laws paint visions of society; or active, as a matrix for the creation of law and culture. An alternative view is suggested: landscapes are opportunities for action, fields within which individuals interact with context in a mutually adaptive relationship. Lawyers are specialized constituents of this adaptation. Lawyers' acts and practices help to constitute the adaptations that shape a given landscape. A teaching module in which it was sought to prompt law students to become aware of the adaptive role of lawyering in landscape is described. The results suggest useful theoretical and methodological insights into landscape as a field of human activity, and the need for further study of lawyering as a force in the construction of landscape.  相似文献   
973.
This paper explores the highly urbanized landscape of the Los Angeles River. Direct encounters with the contemporary river are combined with an historical exploration of some of the developments associated with its transformation into a 51-mile concrete drainage channel. It is suggested that the current landscape of the Los Angeles River not only reveals much about the complex relations between nature and culture in southern California but also illustrates how the contemporary city is marked by a schism between technical conceptions of water control and new attempts to combine river management with wider social and ecological objectives.  相似文献   
974.
The transitional areas that lie between wildlands and urbanized spaces, generally defined as wildland–urban interfaces (WUI), represent an increasing risk factor in Mediterranean areas; these define a new scenario in forest fire fighting and prevention. We have developed a methodological approach in order to assess the hazard and vulnerability of WUI which is based on landscape analysis, on the use of Geographic Information Systems (GIS) techniques and remote sensing. Unlike traditional approaches which are based on local scale characterization of WUI, we propose a progressive multi-scale approach. In order to reach an operative classification of the WUI the methodology was developed in three stages: a regional urban development model, a landscape character assessment and finally, a WUI typology. The last WUI typology has been based on the identification of different urban morphologies and their context within the type of landscape in which they occur.  相似文献   
975.
New design approaches can be observed in an increasing number of botanical gardens due to a desire to improve the effectiveness of environmental interpretation. This paper presents a review of these recent trends in the display of plants based on a search of botanical gardens around the world and on both theory and previous research findings that have focused on understanding people's experience in botanical gardens and other environmental interpretation settings. Four design strategies of plant display were identified, which are referred to here as familiar frames, icons, imitations and manipulations of nature. These typological categories represent recent design approaches useful for establishing stronger relationships between people, plants and associated environmental issues. Further, the potential of such displays as environmental interpretation tools is discussed based on how people perceive them.  相似文献   
976.
This article uses an activity-based understanding of landscape to explore values related to perceived land cover diversity. Perceptions within two user groups, members of landowner families and hiking tourists in a mountain area in western Norway, were related to a simultaneous land cover survey, and compared to experts' evaluations of land cover and to the aims of landscape protection in the area. Users perceived the area as being significantly more diverse and valuable than experts did, which stresses the importance of taking user perception into account in landscape protection and management. Some central landscape values were dependent upon land use outside the boundaries of the protected area. This illustrates that measures within structurally defined land units are not necessarily sufficient for maintenance of landscape values experienced by users. Land use in both respects, as an upholder of values and as a way of experiencing or perceiving them, should receive an increased role in the determination of management units.  相似文献   
977.
民俗文化是地域景观的构成要素,民俗文化的传承对展现地域文化具有重要的意义,在城乡建设中对民俗风情的探索已经成为相关领域研究的热点。本文以西昌邛海缸窑湾度假村景观规划设计方案为例,通过对当地民俗文化从精神层面的解析,提炼成方案设计的手法,探讨如何在地域景观设计中更好地融入民俗文化要素。  相似文献   
978.
ABSTRACT

The Jubilee Church in the south-eastern outskirts of Rome is one of the first buildings constructed with super white reinforced concrete with self-cleaning photocatalytic cement. However, 16 years after the opening of the building, the self-cleaning and colour-preserving properties arising from the titania particles (TiO2) within the concrete mix are not meeting the design requirements and the concrete is showing premature evidence of decay. While the form of the decay is affecting the appearance of the building and not its structural soundness, the ageing pattern of the building's components is resulting in a high maintenance cost, one not easily affordable within the ordinary budget supported by a small parish. This study comprises the first comprehensive step in understanding the causes of the accelerated ageing pattern of the concrete, highlighting methods to improve the long-term durability of the concrete and therefore reduce the cost of its maintenance. Moreover, this research offered the opportunity to test the durability and the effectiveness of the TiO2 in the real conditions on an actual building featuring non-standard geometries. The findings highlight how the ageing pattern directly connects with the geometry of the building and inadequate consideration of the local weathering at the design stage.  相似文献   
979.
唐克扬 《新建筑》2013,(6):36-43
水滨的再开发涉及两组彼此交叉的关系:"城市"和"自然","新"和"旧"。试图通过具体的、个人化的角度理解藉由"设计"之名出现的城市水滨再开发,一个"理想"的案例一方面揭示出当代城市设计的策略,另一方面也暴露了实践滞后于理论的现状,无论"城市"还是"设计"都缺乏明确的定义或共识,因前者是一种事实的积累及总体的视角,后者却是"遂其所愿"的思路。故"城市设计"的危机与这两种思路的差异性有关,其出路在于如何调和这种差异。  相似文献   
980.
王慧  吴晓  王承慧 《新建筑》2013,(4):140-146
以常州市新北区孟城、万绥两座运河古镇为例,探寻古镇传统空间格局的解析方法。以点、线、面、自然基底四要素为切入点,从构成要素和组合方式两方面对比分析了在传统条件和现实状况下古镇空间构成要素的分布特征与组合方式之异同,以期了解古镇传统空间格局特质,并为日后的保护管控及规划提供依据。  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