全文获取类型
收费全文 | 39080篇 |
免费 | 4677篇 |
国内免费 | 3410篇 |
专业分类
电工技术 | 3341篇 |
技术理论 | 10篇 |
综合类 | 5561篇 |
化学工业 | 666篇 |
金属工艺 | 379篇 |
机械仪表 | 1878篇 |
建筑科学 | 2436篇 |
矿业工程 | 1098篇 |
能源动力 | 332篇 |
轻工业 | 530篇 |
水利工程 | 1095篇 |
石油天然气 | 508篇 |
武器工业 | 915篇 |
无线电 | 6232篇 |
一般工业技术 | 1957篇 |
冶金工业 | 1530篇 |
原子能技术 | 97篇 |
自动化技术 | 18602篇 |
出版年
2024年 | 67篇 |
2023年 | 415篇 |
2022年 | 847篇 |
2021年 | 1044篇 |
2020年 | 1155篇 |
2019年 | 832篇 |
2018年 | 782篇 |
2017年 | 1053篇 |
2016年 | 1281篇 |
2015年 | 1497篇 |
2014年 | 2807篇 |
2013年 | 2571篇 |
2012年 | 3114篇 |
2011年 | 3169篇 |
2010年 | 2455篇 |
2009年 | 2696篇 |
2008年 | 2912篇 |
2007年 | 3131篇 |
2006年 | 2842篇 |
2005年 | 2505篇 |
2004年 | 2151篇 |
2003年 | 1903篇 |
2002年 | 1361篇 |
2001年 | 1114篇 |
2000年 | 860篇 |
1999年 | 555篇 |
1998年 | 376篇 |
1997年 | 304篇 |
1996年 | 252篇 |
1995年 | 198篇 |
1994年 | 182篇 |
1993年 | 135篇 |
1992年 | 91篇 |
1991年 | 74篇 |
1990年 | 44篇 |
1989年 | 51篇 |
1988年 | 42篇 |
1987年 | 28篇 |
1986年 | 23篇 |
1985年 | 29篇 |
1984年 | 36篇 |
1983年 | 29篇 |
1982年 | 16篇 |
1981年 | 13篇 |
1980年 | 17篇 |
1979年 | 15篇 |
1977年 | 8篇 |
1965年 | 10篇 |
1964年 | 11篇 |
1961年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
Asli Agirbas 《建筑学研究前沿(英文版)》2020,9(4):940-950
This study aims to test two hypotheses: teaching building information modeling (BIM) in relation to construction science provides students with a remarkable understanding of the nature of construction science (Hypothesis 1), and if the student has positive attitude toward the use of the BIM program, then efficiency by which construction science is taught by its means is improved (Hypothesis 2). Results and process of a case study with a novel teaching methodology were discussed in terms of the benefits of the students. A questionnaire study was conducted on the student group with which the case study was performed to test each student's attitude. Results were evaluated statistically. When BIM is integrated with the teaching of basic construction courses within architecture degree programs, the students understood the building system principles simply and effectively. As a result of the statistical analysis, the students find the applied method effective. Moreover, their attitude toward BIM affects the process. 相似文献
33.
Puxian Xiong Chibin Zheng Mingying Peng Zhihao Zhou Feifei Xu Kexin Qin Yiyu Hong Zhijun Ma 《Journal of the American Ceramic Society》2020,103(12):6922-6931
Till now, many doped persistent luminescence (PersL) phosphors have been investigated and found various applications in such as bioimaging, photocatalysis and information storage, but introducing PersL emitters into a proper host is mostly complex. In this research, a self-activated PersL phosphor Ba2Zr2Si3O12 (BZSO) is prepared by solid state reaction. By adding NH4Cl, the self-activated PersL intensity is evidently enhanced. The trap depths and concentrations are examined by thermoluminescence spectra. Meanwhile, Bi3+ ions are introduced into BZSO and show wide band photoluminescence (PL) from 300 to 600 nm. Moreover, the PL of Bi3+ is tunable under excitation by 265-350 nm lights. Furthermore, as a proof-of-concept design, we designed a patterned quick response (QR) code based on the self-activated PersL of BZSO, and the information of “South China University of Technology (SCUT)” can be read out by the code scanning technology. Bi3+-doped BZSO phosphors are suggested to provide potential applications in information storage by its self-activated PersL, and to excite researchers to study the tunable PL in Bi3+-doped phosphor. 相似文献
34.
35.
本文建立了PC结构施工全过程的BIM模型及有限元分析模型,对施工过程进行数值模拟与动态、静态监测,对装配式结构进行了结构性能评价,为结构可视化施工监测提供了技术支持。 相似文献
36.
随着社会的发展,信息和文化资源大多来自于图书和网络,而高校图书馆有着丰富的藏书和网络资源,因此,高校图书馆网络资源的共建共享就是科学文化发展的必然结果。那么如何实现网络资源的共建共享,网络资源的共建共享又存在哪些问题,又该如何解决,本文在这里就简单的浅谈一下高校图书馆的资源共享。 相似文献
37.
Evidence suggests that transient visual information, such as animations, may be more challenging to learn than static visualizations. However, when a procedural-manipulative task is involved, our evolved embodied cognition seems to reverse this transitory challenge. Hence, for object manipulative tasks, instructional animations may be more suitable than statics. We investigated this argument further by comparing animations with statics using a Lego task shown to university students, by examining three potential moderators of effectiveness: (a) the environment of manipulation (virtual or physical), (b) the quality of visual information (focused or unfocused), and (c) the presence of hands (no hands or with hands). In Experiment 1 we found an advantage of animation over statics, and no differences among the environments. In Experiment 2, we again observed an animation advantage, a small advantage of focused static information compared to unfocused static information, and a positive effect of not showing the hands. 相似文献
38.
Colin J. Torney Tommaso Lorenzi Iain D. Couzin Simon A. Levin 《Journal of the Royal Society Interface》2015,12(103)
Animal groups in nature often display an enhanced collective information-processing capacity. It has been speculated that natural selection will tune this response to be optimal, ensuring that the group is reactive while also being robust to noise. Here, we show that this is unlikely to be the case. By using a simple model of decision-making in a dynamic environment, we find that when individuals behave rationally and are subject to selection based on their accuracy, optimality of collective decision-making is not attained. Instead, individuals overly rely on social information and evolve to be too readily influenced by their neighbours. This is due to a classic evolutionary conflict between individual and collective interest. The result is a sub-optimal system that is poised on the cusp of total unresponsiveness. Individuals in the evolved group exhibit delayed reactions to changes in the environment, before responding with rapid, socially reinforced transitions, reminiscent of familiar human and animal social systems (markets, stampedes, fashions, etc.). Our results demonstrate that behaviour of this type may not be pathological, but instead could represent an evolutionary attractor for such collective systems. 相似文献
39.
刘杰生 《计算机与数字工程》2015,(6)
论文从硬件设备、软件服务、数据资源和任务调度等几个方面对美国海军在开发构建全舰计算环境基础设施过程中标准化的设计方法进行深入分析。通过采用标准化的计算、显示、存储等硬件资源并进行整合,提升硬件资源的利用效率和共用水平;开发各个层次的公共应用功能软件并形成标准化的服务,将软件和硬件解耦,达到应用与数据分离,使得基于TSCEI的信息化装备的构建更加快速灵活,开放性更好,可扩展性及升级能力大为增强。标准化在 TSCEI的推行和实施中起着至关重要的作用。标准化设计方法对构建我军新型信息基础设施具有较重要的借鉴作用。 相似文献
40.
如今我国信息化技术全面发展,尤其对于工程测量工作领域来讲,不管是在工程建设和管理方面都产生不小的支撑引导效用。由此,笔者具体结合如今工程建设信息化测绘核心任何以及设备布置细节,进行结构整体安全管理周期和周边地理空间信息技术发展能效整理解析,试图将工程测量最新发展机遇和技术挑战问题处理完全。希望能够借此为日后一定时期范围内相关工程测量规划主体提供合理指导性建议内容,最终为我国各类工程事业可持续发展前景绽放奠定深刻适应基础。 相似文献