全文获取类型
收费全文 | 1992篇 |
免费 | 91篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 25篇 |
综合类 | 16篇 |
化学工业 | 570篇 |
金属工艺 | 31篇 |
机械仪表 | 33篇 |
建筑科学 | 144篇 |
矿业工程 | 3篇 |
能源动力 | 27篇 |
轻工业 | 171篇 |
水利工程 | 11篇 |
石油天然气 | 4篇 |
无线电 | 119篇 |
一般工业技术 | 382篇 |
冶金工业 | 183篇 |
原子能技术 | 16篇 |
自动化技术 | 353篇 |
出版年
2023年 | 24篇 |
2022年 | 48篇 |
2021年 | 65篇 |
2020年 | 37篇 |
2019年 | 46篇 |
2018年 | 46篇 |
2017年 | 41篇 |
2016年 | 52篇 |
2015年 | 47篇 |
2014年 | 73篇 |
2013年 | 100篇 |
2012年 | 91篇 |
2011年 | 161篇 |
2010年 | 106篇 |
2009年 | 112篇 |
2008年 | 107篇 |
2007年 | 86篇 |
2006年 | 87篇 |
2005年 | 74篇 |
2004年 | 70篇 |
2003年 | 60篇 |
2002年 | 51篇 |
2001年 | 45篇 |
2000年 | 44篇 |
1999年 | 46篇 |
1998年 | 43篇 |
1997年 | 35篇 |
1996年 | 21篇 |
1995年 | 26篇 |
1994年 | 34篇 |
1993年 | 15篇 |
1992年 | 13篇 |
1991年 | 24篇 |
1990年 | 17篇 |
1989年 | 19篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 5篇 |
1985年 | 13篇 |
1984年 | 12篇 |
1983年 | 12篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1931年 | 3篇 |
排序方式: 共有2088条查询结果,搜索用时 15 毫秒
151.
152.
In this paper we present new work done on the bin-picking problem. The work was triggered by the advent of a new solid state range camera which enables the economic and robust use of range imagery in industrial robotic automation tasks. The application presented is that of pick-and-place of randomly oriented but known polyhedral objects in an industrial robotic work cell. The algorithms for segmentation, pose estimation, and grasp point determination are presented along with practical results from a real industrial grade work cell. 相似文献
153.
A crucial component of the interaction between ATM's and the Internet's Quality of Service (QoS) architectures is the efficient mapping of RSVP (Resource reSerVation Protocol) as the Internet's signalling protocol onto the according ATM mechanisms. In particular, this article focuses on one of the most contrary characteristics of RSVP and ATM signalling. This is the support for heterogeneous reservations by RSVP over the ATM subnetwork, taking into account that ATM only allows for a homogeneous QoS within a single Virtual Circuit (VC). We present previous approaches to the solution of this problem and argue for more sophisticated and efficient approaches to manage ATM VCs taking into consideration ATM tariffs and resource consumption. 相似文献
154.
155.
Ralf Bandorf Dr. Wolfgang Diehl Dipl.‐Ing Ulrike Heckmann Dipl.‐Phys. Simone Kondruweit Dr. Andreas Pflug Dr. Harald Holeczek Dipl.‐Ing. Martin Metzner Dr. Udo Klotzbach Dr. Andreas Leson Dr. Otmar Zimmer Dr. 《真空研究与实践》2008,20(5):14-19
Propositions and Trends – With Functional Surfaces into the Future Functional surfaces are the key to innovative products. Already today the properties, lifetime, and costs for most industrial and consumer products are determined by functionalised surfaces. Three Fraunhofer Institutes supported by the BMBF investigated the actual state of the art of production technology regarding functional surfaces, their future perspectives and the research and development demand. The results are published in the study “Production technology for the generation of functional surfaces” available at info@ist.‐ fraunhofer.de and the essentials are summarised in this article. 相似文献
156.
157.
Dr. Ralf Knackstedt Dipl.-Wirt.-Inform. Jens Pöppelbuß Dr. Axel Winkelmann 《WIRTSCHAFTSINFORMATIK》2008,50(3):235-247
The article presents results of an internet research on product-service systems. Web sites showing interesting practical examples and studies available online are presented to point out the practical relevance of innovative combinations of products and services. The multiplicity of research projects found on the internet shows that this phenomenon is also discussed intensively in research. These projects have been categorized by analyzing their web sites. Furthermore, the results of the internet research highlight a high diversity of terms for describing the concept of product-service systems. As a consequence, orientation in this subject area is hindered. 相似文献
158.
Ralf Ackermann Thomas Knoblauch Dipikar Kumar Klaus Unger Mechthild Enderle 《Journal of Low Temperature Physics》2001,122(3-4):143-146
The static susceptibility of solid oxygen condensed into nanoporous matrices is measured as a function of temperature and pore diameter. The drastic changes of the qualitative behaviour are interpreted as a cross-over from three- to one-dimensional behaviour. 相似文献
159.
Ralf Schützhold 《Journal of Low Temperature Physics》2008,153(5-6):228-243
A sweep through a quantum phase transition by means of a time-dependent external parameter (e.g., pressure) entails non-equilibrium phenomena associated with a break-down of adiabaticity: At the critical point, the energy gap vanishes and the response time diverges (in the thermodynamic limit). Consequently, the external time-dependence inevitably drives the system out of equilibrium, i.e., away from the ground state, if we assume zero temperature initially. In this way, the initial quantum fluctuations can be drastically amplified and may become observable—especially for symmetry-breaking (restoring) transitions. By means of several examples, possible effects of these amplified quantum fluctuations are studied and universal features (such as freezing) are discussed. 相似文献
160.
Susanne Liemersdorf Ralf Riedel Jürgen Oberle 《Journal of the American Ceramic Society》2008,91(1):325-328
Silicon oxycarbide (SiOC)-based ceramics were synthesized by pyrolysis of a commercial polysiloxane containing MoSi2 and ceramic filler particles. The influence of different gas atmospheres on the chemical composition and on the phase formation of the filled Si–O–C ceramic during the pyrolysis process up to elevated temperatures of above 1200°C has been studied. The pyrolysis gas composition in the furnace during pyrolysis was measured with an in situ gas analyzer. Both the core and the surface of bulk samples were investigated with respect to composition in order to take the changes on the rim area of the specimens into account. The influence of hydrogen gas on the compositional gradient of the resulting ceramic material was derived from samples investigated by polarization microscopy, X-ray diffraction (XRD), and micro-XRD (μ-XRD). 相似文献