全文获取类型
收费全文 | 6888篇 |
免费 | 340篇 |
国内免费 | 357篇 |
专业分类
电工技术 | 95篇 |
技术理论 | 8篇 |
综合类 | 928篇 |
化学工业 | 679篇 |
金属工艺 | 99篇 |
机械仪表 | 192篇 |
建筑科学 | 576篇 |
矿业工程 | 200篇 |
能源动力 | 131篇 |
轻工业 | 319篇 |
水利工程 | 119篇 |
石油天然气 | 80篇 |
武器工业 | 1025篇 |
无线电 | 647篇 |
一般工业技术 | 687篇 |
冶金工业 | 620篇 |
原子能技术 | 45篇 |
自动化技术 | 1135篇 |
出版年
2024年 | 8篇 |
2023年 | 59篇 |
2022年 | 86篇 |
2021年 | 127篇 |
2020年 | 125篇 |
2019年 | 102篇 |
2018年 | 86篇 |
2017年 | 332篇 |
2016年 | 352篇 |
2015年 | 350篇 |
2014年 | 475篇 |
2013年 | 379篇 |
2012年 | 332篇 |
2011年 | 552篇 |
2010年 | 424篇 |
2009年 | 469篇 |
2008年 | 361篇 |
2007年 | 441篇 |
2006年 | 434篇 |
2005年 | 327篇 |
2004年 | 276篇 |
2003年 | 275篇 |
2002年 | 205篇 |
2001年 | 190篇 |
2000年 | 166篇 |
1999年 | 128篇 |
1998年 | 73篇 |
1997年 | 63篇 |
1996年 | 52篇 |
1995年 | 36篇 |
1994年 | 48篇 |
1993年 | 24篇 |
1992年 | 20篇 |
1991年 | 14篇 |
1990年 | 25篇 |
1989年 | 22篇 |
1988年 | 11篇 |
1986年 | 12篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1966年 | 6篇 |
1965年 | 6篇 |
1964年 | 9篇 |
1963年 | 6篇 |
1961年 | 5篇 |
1960年 | 5篇 |
1958年 | 5篇 |
1955年 | 6篇 |
排序方式: 共有7585条查询结果,搜索用时 250 毫秒
61.
AbstractThe potential well-being benefits associated with the use of privately owned greenspaces in working environments have received little research attention. Given the growing evidence on the restorative benefits of urban greenspace, and the fact that many people spend most of their daily hours at the workplace, the question of whether physical access to green environments from workplaces can promote well-being is a pertinent one. Person–environment relationships in peri-urban business sites were investigated in a series of semi-structured ‘go-along’ interviews with employees at Scottish science parks. Workers described a range of well-being benefits from outdoor breaks and associated these with qualities of the environment. Semi-natural and informally landscaped areas were most strongly associated with restoration during the working day. The implications of the findings for the planning and design of business sites at the urban fringe are explored. 相似文献
62.
木文试图从科学技术的角度回顾科技与城市发展的历史,分析近代科技进步与城市发展的关系,以及现代科技进步在丰富和扩展城市规划理论内容中的作用,进而揭示21世纪与科技进步相关的城市发展三大趋势。 相似文献
63.
J.P. O’Sullivan R.A. ArcherR.G.J. Flay 《Journal of Wind Engineering & Industrial Aerodynamics》2011,99(1):65-77
In computational wind engineering the neutrally stable atmospheric boundary layer (ABL) is often simulated using the standard k-ε model. The application of boundary conditions that are inconsistent with the profiles used at the inflow boundary causes streamwise gradients in the solution and prevents the simulation of a horizontally homogeneous boundary layer. In the present work these problems are overcome by applying a simple extension of the shear stress boundary condition at the top of the domain and by using one-dimensional models to generate inflow profiles in equilibrium with the ground boundary condition. This procedure allows the impact of the inconsistent boundary conditions to be quantitatively assessed. It is shown that inconsistent boundary conditions at the top of the domain result in erroneous streamwise gradients throughout the domain. These errors are reduced by enlarging the domain in the vertical direction but are not removed. The errors are also found in simulations with idealised and real topography included in the domain. A brief discussion of the impact of the errors on simulations of wind energy projects is given. 相似文献
64.
长期的封建专制制度造成科学和民主精神的缺乏,是建筑设计失去创造性的根本原因。殖民主义和后殖民主义的历史影响难以在短时间内消除,崇洋、尚洋的心理使建筑设计停留在形式的摹仿。本文从历史文化角度,分析这两方面对中国社会产生的负面影响出发,阐述建筑设计缺乏创造性的历史渊源。 相似文献
65.
广州是我国改革开放的前沿城市,又是拥有岭南地方特色的历史文化名城,其城市建设呈现出多元化、多方向的发展特点,也为建筑创作提供了丰富的素材和广阔的实践基地。身为广州高校的建筑学专业如何利用区位优势,培养创新人才,更好地为社会服务来满足时代需求,是摆在我们面前的新课题。 相似文献
66.
Heather Lovell 《Housing Studies》2005,20(5):815-829
Economic theory about supply and demand suggests that if consumer demand for a product increases then producers respond by increasing supply. In the UK housing market there is emerging evidence of consumer demand for low energy housing, yet little has been built to date by private sector housebuilders: existing low energy housing is largely within the social housing and self-build sectors. Ideas from science and technology studies (STS) are introduced to help further understanding of why the housing market might be slow to respond to changing consumer preferences. Although standard economic concepts concerning costs and price are able in part to explain the situation, greater attention to socio-technical issues highlights some of the reasons why innovation and change are difficult to effect. The housing market is best viewed as a socio-technical system, whereby the social and the technical are interlinked. 相似文献
67.
Y. Gao 《Journal of Wind Engineering & Industrial Aerodynamics》2005,93(2):115-135
In this paper, air approach flow moving towards a cube will be studied using computational fluid dynamics (CFD). The Reynolds Averaging of Navier-Stokes (RANS) equation types of k-ε turbulence model are used. Some RANS predicted results are compared with different upstream air speeds. Flow separation at the corner above the top of the cube, level of separation and reattachment are investigated. Reference is made to the experimental data on wind tunnels reported in the literature.A method similar to ‘recirculation bubble promoter’ is used for different approach flow speed distributions. Problems encountered in numerical simulations due to the sharp corner are discussed with a view to obtaining better prediction on recirculation flow in regions above the top of the cube. Correlations between the turbulent kinetic energy above the cube and the recirculation bubble size are derived for different distributions of approach flow speed.By limiting the longitudinal velocities in the first cell adjacent to the sharp edge of the cube or rib, and making good use of the wall functions at the intersection cells of the velocity components, positions of maximum turbulent kinetic energy and the flow separation and reattachment can be predicted by a standard k-ε model. The results agree with those obtained in the experiments. 相似文献
68.
69.
水力学是土建、水利类学科专业必修课程,也是本科教育阶段给排水科学与工程的核心专业基础课。课程的教学效果对本科生后期学习涉及水力学相关知识的专业课程至关重要。文章针对提升给排水科学与工程专业水力学课程教学质量进行探索性研究。研究认为采用多元教学模式,例如自主互动、"粉笔+黑板"板书教学与视频动画等多媒体相结合的形式,是一种理想的教学模式,其将启发式和讲授式教学相融合,努力提高学生的动手实践能力,积极引导本科生自主创新。这种教学模式可以充分调动学生学习积极性,促使教学质量得到提升,最终取得良好的教学效果。 相似文献
70.