全文获取类型
收费全文 | 8561篇 |
免费 | 333篇 |
国内免费 | 311篇 |
专业分类
电工技术 | 217篇 |
综合类 | 288篇 |
化学工业 | 231篇 |
金属工艺 | 401篇 |
机械仪表 | 1335篇 |
建筑科学 | 409篇 |
矿业工程 | 128篇 |
能源动力 | 121篇 |
轻工业 | 101篇 |
水利工程 | 29篇 |
石油天然气 | 197篇 |
武器工业 | 98篇 |
无线电 | 637篇 |
一般工业技术 | 371篇 |
冶金工业 | 196篇 |
原子能技术 | 65篇 |
自动化技术 | 4381篇 |
出版年
2024年 | 8篇 |
2023年 | 59篇 |
2022年 | 85篇 |
2021年 | 127篇 |
2020年 | 156篇 |
2019年 | 149篇 |
2018年 | 124篇 |
2017年 | 145篇 |
2016年 | 203篇 |
2015年 | 212篇 |
2014年 | 400篇 |
2013年 | 340篇 |
2012年 | 446篇 |
2011年 | 604篇 |
2010年 | 403篇 |
2009年 | 455篇 |
2008年 | 531篇 |
2007年 | 668篇 |
2006年 | 681篇 |
2005年 | 661篇 |
2004年 | 582篇 |
2003年 | 518篇 |
2002年 | 416篇 |
2001年 | 323篇 |
2000年 | 204篇 |
1999年 | 199篇 |
1998年 | 115篇 |
1997年 | 70篇 |
1996年 | 60篇 |
1995年 | 46篇 |
1994年 | 34篇 |
1993年 | 46篇 |
1992年 | 30篇 |
1991年 | 7篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 17篇 |
1979年 | 4篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有9205条查询结果,搜索用时 31 毫秒
31.
高分子量聚合物的分子量对岩心渗透率的适应性研究 总被引:12,自引:2,他引:10
本文通过不同分子量的高分子量聚合物(部分水解聚丙烯酰胺)在不同渗透率岩心中的流动实验,研究了高分子量聚合物的分子量与岩心渗透率之间的匹配关系,为大庆油田采用高分子量聚合物驱油提供决策依据。 相似文献
32.
P. Balle H. Bockhorn B. Geiger N. Jan S. Kureti D. Reichert T. Schrder 《Chemical Engineering and Processing: Process Intensification》2006,45(12):1065-1073
This study deals with the development of a laboratory bench for the practical evaluation of catalysts that are useful for the direct conversion of NOx and soot in the exhaust of diesel engines. The employed model exhaust is generated by using a diffusion burner with additionally dosing some gaseous components to the burner gas to obtain a realistic feed composition. The produced soot is extensively characterized by employing thermogravimetry, transmission electron microscopy, N2 physisorption and temperature programmed techniques. The results of the different characterization methods show that the present soot is suitable for the intended catalytic investigations. The simultaneous conversion of NOx and soot is examined like in practice, i.e. the soot is separated from the tail gas by a diesel particulate filter (DPF) that is coated with the catalyst. The deposited soot is then catalytically converted by NOx and O2 to form N2 and CO2. The conversions of NOx and soot are measured by exclusively applying gas analysers, whereby a special experimental procedure is developed to determine the soot removal. Hence, additional soot related analytics are not required. To show the suitability of the constructed bench a Pt/Fe2O3/β-zeolite sample is taken as test catalyst that is reported to be very active in NOx/soot reaction. The measurements performed with and without catalyst clearly show the effect of the used sample in simultaneous NOx/soot conversion. We therefore consider the constructed laboratory bench to be a useful tool for testing and ranking catalytic materials. 相似文献
33.
Internet环境下漫游系统中的视点控制技术 总被引:3,自引:0,他引:3
在研究了基于Web的虚拟真实漫游系统的应用前景的基础上,利用VRML的网络特性以及内置接口语言Java和JavaScript,对系统中的视点绑定、视点动画交互等关键技术进行了详细的阐述,并给出了相应的VRML程序。 相似文献
34.
针对辽河油田高凝油区块注高温热水(85—95℃)引起的腐蚀、结垢,开展了室内和现场缓蚀、阻垢试验;分析了不同温度下注水的腐蚀情况,对比、考察了不同的缓蚀剂、阻垢剂及其复配物,得出了如下认识:在注高温热水条件下直接采用常温下使用的防腐蚀、防垢方法是不可行的,必须有针对性地进行高温条件下防腐蚀、防垢的实验研究工作。 相似文献
35.
基于虚拟仪器技术的多线程数据采集系统 总被引:4,自引:0,他引:4
本文论述了如何利用虚拟仪器技术以及多线程技术来进行数据采集,并介绍了在工业中的实际应用。 相似文献
36.
Complementary modelling of fluid separation processes 总被引:1,自引:0,他引:1
Optimal functioning of numerous technological processes depends primarily on relevant process design, properly selected column internals and sufficient understanding of the process behaviour. This can be achieved only with the help of accurate and reliable process models capable of considering process rates in a rigorous way, with respect to both transport phenomena and chemistry. In this article, a new modelling concept called complementary modelling is suggested for a large class of fluid separation processes. Since the conditions and criteria for these processes vary considerably, it is impossible to develop a unified modelling approach. Instead, a reasonable and effective combination of different modelling approaches provides solutions to many present and future tasks. The complementary modelling is discussed in detail and illustrated with several case studies. 相似文献
37.
A quantitative analysis of the effectiveness of laparascopy and endoscopy virtual reality simulators
Shankar Srinivasan Author Vitae Dinesh P. Mital Author VitaeAuthor Vitae 《Computers & Electrical Engineering》2006,32(4):283-298
The increasing use of virtual reality (VR) simulators in surgical training makes it imperative that definitive studies be performed to assess their training effectiveness. Indeed in this paper we report the meta-analysis of the efficacy of virtual reality simulators in (1) the transference of skills from the simulator training environment to the operating room and (2) their ability to discriminate between the experience levels of its users. The task completion time and the error score were the two study outcomes collated and analyzed in this meta-analysis. Sixteen studies were identified from a computer-based literature search (1996-2004). The meta-analysis of the random-effects model (because of the heterogeneity of the data) revealed that training on virtual reality simulators did lessen the time taken to complete a given surgical task as also clearly differentiate between the experienced and the novice trainees. Meta-analytic studies such as the one reported here would be very helpful in the planning and setting up of surgical training programs and for the establishment of reference ‘learning curves’ for a specific simulator and surgical task. If any such programs already exist they can then indicate the improvements to be made in the simulator used such as providing for more variety in their case scenarios based on the state and/or rate of learning of the trainee. 相似文献
38.
In this paper, we present the findings from an extensive study of the use of virtual reality (VR) models in large construction projects. The study includes two parts: The first part presents a quantitative questionnaire designed to investigate how VR models are experienced and assessed by the workforce at a building site. The second part includes a qualitative field survey of how VR models can be applied and accepted by professionals in the design and planning process of a large pelletizing plant. Through mainly studying persons who had little or no experience with advanced information technology (IT), we hoped to reveal the attitudes of the average person working at a construction site rather than of an IT expert. In summary, the study shows that the VR models in both projects have been very useful and well accepted by the users. Today’s information flow is, from a general point of view, considered to be insufficient and the hypothesis is that using VR models in the construction process have the potential to minimize waste of resources and improve the final result. 相似文献
39.
(Department of Automation & Computer Baotou Iron &Steel Instetute Baotou PRC) Wang ZhichunLi Wentao(Department of Net work Baotou Filiale of Inner MongoliaMobile Corporation Baotou PRC)Yang Zhanping 《微计算机信息》2003,19(5):45-45
This paper introduces hardware connections between computer and intellectualized instrument based on 89c51 sin-glechip .It gives the techniques to compile internet applications of Virtual Instruments with Delphi6. 相似文献
40.
虚拟企业模型并行仿真研究 总被引:4,自引:0,他引:4
随着各种全新的制造理念,特别是虚拟企业的出现,企业模型的规模不断扩大,使目前存在的大多数企业模型仿真系统的效率大大下降。该文针对此问题,通过深入分析虚拟企业模型结构,并在已有的构件化企业建模体系CEMS及其仿真系统的基础上,结合异步仿真技术和多线程技术提出了一种分层式企业模型仿真体系结构,为虚拟企业模型的快速高效的仿真提供了一种有效的方法。 相似文献