全文获取类型
收费全文 | 2958篇 |
免费 | 104篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 26篇 |
综合类 | 3篇 |
化学工业 | 770篇 |
金属工艺 | 39篇 |
机械仪表 | 36篇 |
建筑科学 | 195篇 |
矿业工程 | 63篇 |
能源动力 | 40篇 |
轻工业 | 265篇 |
水利工程 | 56篇 |
石油天然气 | 1篇 |
无线电 | 214篇 |
一般工业技术 | 442篇 |
冶金工业 | 276篇 |
原子能技术 | 22篇 |
自动化技术 | 619篇 |
出版年
2023年 | 23篇 |
2021年 | 34篇 |
2019年 | 26篇 |
2018年 | 32篇 |
2017年 | 32篇 |
2016年 | 77篇 |
2015年 | 69篇 |
2014年 | 100篇 |
2013年 | 129篇 |
2012年 | 160篇 |
2011年 | 147篇 |
2010年 | 98篇 |
2009年 | 100篇 |
2008年 | 121篇 |
2007年 | 121篇 |
2006年 | 151篇 |
2005年 | 84篇 |
2004年 | 77篇 |
2003年 | 59篇 |
2002年 | 69篇 |
2001年 | 44篇 |
2000年 | 59篇 |
1999年 | 63篇 |
1998年 | 88篇 |
1997年 | 64篇 |
1996年 | 54篇 |
1995年 | 41篇 |
1994年 | 47篇 |
1993年 | 48篇 |
1992年 | 36篇 |
1991年 | 43篇 |
1990年 | 42篇 |
1989年 | 34篇 |
1988年 | 28篇 |
1987年 | 29篇 |
1986年 | 27篇 |
1985年 | 31篇 |
1984年 | 35篇 |
1983年 | 28篇 |
1982年 | 38篇 |
1981年 | 37篇 |
1980年 | 25篇 |
1979年 | 34篇 |
1978年 | 28篇 |
1977年 | 32篇 |
1976年 | 42篇 |
1975年 | 31篇 |
1974年 | 31篇 |
1973年 | 25篇 |
1970年 | 28篇 |
排序方式: 共有3067条查询结果,搜索用时 15 毫秒
1.
Jens Mller Anne Busch Christian Berens Helmut Hotzel Andreas Burkovski 《International journal of molecular sciences》2021,22(7)
Corynebacterium silvaticum is a newly identified animal pathogen of forest animals such as roe deer and wild boars. The species is closely related to the emerging human pathogen Corynebacterium ulcerans and the widely distributed animal pathogen Corynebacterium pseudotuberculosis. In this study, Corynebacterium silvaticum strain W25 was characterized with respect to its interaction with human cell lines. Microscopy, measurement of transepithelial electric resistance and cytotoxicity assays revealed detrimental effects of C. silvaticum to different human epithelial cell lines and to an invertebrate animal model, Galleria mellonella larvae, comparable to diphtheria toxin-secreting C. ulcerans. Furthermore, the results obtained may indicate a considerable zoonotic potential of this newly identified species. 相似文献
2.
Seidel A.R. Bisogno F.E. Pinheiro H. do Prado R.N. 《Industrial Electronics, IEEE Transactions on》2003,50(6):1267-1274
This paper presents a simple alternative for an electronic ballast operating in self-sustained oscillating mode with dimming capability for fluorescent lamps. A simple modification in one of the gate drivers side circuit allows the lamp to dim without compromising the simplicity, reliability, and low cost which characterize the self-oscillating electronic ballast (SOEB). A qualitative analysis is presented to explain the behavior of the proposed self-oscillating electronic ballast with dimming feature. In addition, the stability and the key equations for the design are derived using the extended Nyquist criterion and describing function method. Experimental results from two 40-W electronic ballasts are presented to demonstrate the performance and to validate the analysis carried out. 相似文献
3.
4.
5.
Prof. Dr.-Ing. Thorsten Spitta Dipl. Ing. Helmut Schmidpeter 《WIRTSCHAFTSINFORMATIK》2002,44(2):141-150
This paper analyses the characteristics of software houses as service providers. The tasks of internal IT-services are determined from these characteristics and a reporting system for the IT-controlling is outlined. The concept results from the analysis of one of the 25 largest German software houses. The paper concludes with a case study of the fiscal year 2000 IT-controlling report of the above-mentioned firm. 相似文献
6.
7.
Heinz Blenke Beate Farys-Kahle Carl-Max Freiherr Von Meysenbug Helmut Weimer 《化学,工程师,技术》1985,57(5):381-390
Rationalizing drawings for chemical apparatus . For small and medium-sized manufacturers of apparatus, producing drawings may constitute a disproportionate waste of time and personnel, particularly when no new designs are involved but only modification or improvement of drawings supplied by the customer. One possibility for rationalizing drawing is to simplify the old-fashioned approach by using symbols for frequently drawn or standard items, or by listing alphanumerically. This presumes a kind of systematization permitting determination of those symbols and their reasonable use, as well facilitating rationalization by means of data processing. There are different approaches to computer-aided drawing (from computer controlled drawing-board to interactive screens); here a CAD programme is presented which was especially developed for graphic presentation of chemical apparatus, and which can be used without learning a programming language. 相似文献
8.
In recent years, a wide range of generalized barycentric coordinates has been suggested. However, all of them lack control over derivatives. We show how the notion of barycentric coordinates can be extended to specify derivatives at control points. This is also known as Hermite interpolation. We introduce a method to modify existing barycentric coordinates to higher order barycentric coordinates and demonstrate, using higher order mean value coordinates, that our method, although conceptually simple and easy to implement, can be used to give easy and intuitive control at interactive frame rates over local space deformations such as rotations. 相似文献
9.
Here, we describe the development of a reacting flow multi-species/combustion methodology, implemented as an extension to the differential reduced ejector analysis (DREA) computer program [Mathematical and computer modeling, vol. 31, 2000, p. 21; Appl. Math. Model. 25 (2001) 427; Comput. Math. Appl. 43(10–11); NASA Contractor Report, 1998]. Use of the single fluid IVP solver framework that was developed for the original DREA model has been directly coupled into the combustion formulation. With these modifications, the analysis has an elementary single step reaction Fuel+Oxidizer→Product combustion capability. Though approximate in nature, the simplicity and efficiency of the DREA formulation make it suitable for its original niche, namely design and preliminary design environments where more complex and expensive models may be inappropriate. 相似文献
10.