全文获取类型
收费全文 | 5347篇 |
免费 | 220篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 86篇 |
综合类 | 30篇 |
化学工业 | 1534篇 |
金属工艺 | 98篇 |
机械仪表 | 99篇 |
建筑科学 | 347篇 |
矿业工程 | 25篇 |
能源动力 | 102篇 |
轻工业 | 421篇 |
水利工程 | 34篇 |
石油天然气 | 3篇 |
无线电 | 325篇 |
一般工业技术 | 1108篇 |
冶金工业 | 533篇 |
原子能技术 | 44篇 |
自动化技术 | 791篇 |
出版年
2023年 | 40篇 |
2022年 | 54篇 |
2021年 | 88篇 |
2020年 | 76篇 |
2019年 | 71篇 |
2018年 | 89篇 |
2017年 | 104篇 |
2016年 | 144篇 |
2015年 | 104篇 |
2014年 | 167篇 |
2013年 | 255篇 |
2012年 | 228篇 |
2011年 | 329篇 |
2010年 | 253篇 |
2009年 | 260篇 |
2008年 | 253篇 |
2007年 | 239篇 |
2006年 | 240篇 |
2005年 | 208篇 |
2004年 | 178篇 |
2003年 | 138篇 |
2002年 | 112篇 |
2001年 | 91篇 |
2000年 | 94篇 |
1999年 | 103篇 |
1998年 | 131篇 |
1997年 | 94篇 |
1996年 | 95篇 |
1995年 | 71篇 |
1994年 | 78篇 |
1993年 | 79篇 |
1992年 | 75篇 |
1991年 | 61篇 |
1990年 | 60篇 |
1989年 | 62篇 |
1988年 | 60篇 |
1987年 | 60篇 |
1986年 | 50篇 |
1985年 | 51篇 |
1984年 | 60篇 |
1983年 | 40篇 |
1982年 | 49篇 |
1981年 | 50篇 |
1980年 | 35篇 |
1979年 | 31篇 |
1978年 | 36篇 |
1977年 | 33篇 |
1976年 | 37篇 |
1975年 | 37篇 |
1973年 | 32篇 |
排序方式: 共有5580条查询结果,搜索用时 31 毫秒
131.
132.
Lutz Wolfgang; Leach Chris; Barkham Michael; Lucock Mike; Stiles William B.; Evans Chris; Noble Rachael; Iveson Steve 《Canadian Metallurgical Quarterly》2005,73(5):904
This study extended client-focused research by using the nearest neighbor (NN) approach, a client-specific sampling and prediction strategy derived from research on alpine avalanches. Psychotherapy clients (N = 203) seen in routine practice settings in the United Kingdom completed a battery of intake measures and then completed symptom intensity ratings before each session. Forecasts of each client's rate of change and session-by-session variability were computed on the basis of that client's NNs (n = 10-50 in different comparisons). Alternative forecasts used linear or log-linear slopes and were compared with an alternative prediction strategy. Results showed that the NN approach was superior to the alternative model in predicting rate of change, though the advantage was less clear for predicting variability. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
133.
Nicole Altvater-Mackensen Gregor Balicki Lucie Bestakowa Bianca Bocatius Johannes Braun Lars Brehmer Verena Brune Kirstina Eigemeier F&#;sun Erdem Ralf Fritscher Anne Jacobs Bernd Klingsporn Marcin Kosinski Julia Kuntze Ju-Ra Lee Anna Osterhage Martin Probost Thorsten Risch Tobias Schmitt Wolfgang G. Stock Anja Sturm Katrin Weller Kerstin Werner 《Scientometrics》2005,63(3):463-529
Summary We operationalize scientific output in a region by means of the number of articles (as in the SciSearch database) per year and technology output by means of the number of patent applications (as in the database of the European Patent Office) per priority year. All informetric analyses were done using the DIALOG online-system. The main research questions are the following: Which scientific and technological fields or topics are most influent within a region and which institutions or companies are mainly publishing articles or holding patents? Do the distributions of regional science and technology fields and of publishing institutions follow the well-known informetric function? Are there - as it is expected - only few fields and few institutions which dominate the region? Is there a connection between the economic power of a region and the regional publication and patent output? Examples studied in detail are seven German regions: Aachen, Düsseldorf, Hamburg, Köln (Cologne), Leipzig - Halle - Dessau, München (Munich), and Stuttgart. Three different indicators were used, science and technology attraction of a region (number of scientific articles and patents), science and technology intensity (articles and patents per 1,000 inhabitants), and science and technology density (articles and patents per 1 billion EURO gross value added). Top region concerning both attraction and intensity is Munich, concerning density it is Aachen. 相似文献
134.
Apoorva G. Wagh Veer Chand Rakhecha Makus Strobl Wolfgang Treimer 《Journal of research of the National Institute of Standards and Technology》2005,110(3):231-235
Super Ultra-Small Angle Neutron Scattering (SUSANS) studies over wave vector transfers of 10–4 nm–1 to 10–3 nm–1 afford information on micrometer-size agglomerates in samples. Using a right-angled magnetic air prism, we have achieved a separation of ≈10 arcsec between ≈2 arcsec wide up- and down-spin peaks of 0.54 nm neutrons. The SUSANS instrument has thus been equipped with the polarized neutron option. The samples are placed in a uniform vertical field of 8.8 × 104 A/m (1.1 kOe). Several magnetic alloy ribbon samples broaden the up-spin neutron peak significantly over the ±1.3 × 10–3 nm–1 range, while leaving the down-spin peak essentially unaltered. Fourier transforms of these SUSANS spectra corrected for the instrument resolution, yield micrometer-range pair distribution functions for up- and down-spin neutrons as well as the nuclear and magnetic scattering length density distributions in the samples. 相似文献
135.
This paper describes the particular motivation for performance analysis in the domain of Enterprise Information Systems (EISs) and argues that the Model Driven Architecture (MDA) is a suitable framework for integrating formal analysis techniques with engineering methods appropriate to the domain. The MDA permits natural and economical modelling of design and analysis domains and the relationships between them, supporting both manual and automatic analysis. It incorporates the Unified Modelling Language (UML), which is extensively used to capture system designs. We present our general modelling approach and outline its use in relating models of Enterprise Java Bean (EJB) applications, annotated using standard profiles, to analysable formal models. 相似文献
136.
Large-scale mapping of boreal forest in SIBERIA using ERS tandem coherence and JERS backscatter data 总被引:3,自引:0,他引:3
Wolfgang Wagner Adrian LuckmanJan Vietmeier Kevin Tansey Heiko BalzterChristiane Schmullius Malcolm Davidson David Gaveau Michael Gluck Thuy Le ToanShaun Quegan Anatoly ShvidenkoAndreas Wiesmann Jiong Jiong Yu 《Remote sensing of environment》2003,85(2):125-144
Siberia's boreal forests represent an economically and ecologically precious resource, a significant part of which is not monitored on a regular basis. Synthetic aperture radars (SARs), with their sensitivity to forest biomass, offer mapping capabilities that could provide valuable up-to-date information, for example about fire damage or logging activity. The European Commission SIBERIA project had the aim of mapping an area of approximately 1 million km2 in Siberia using SAR data from two satellite sources: the tandem mission of the European Remote Sensing Satellites ERS-1/2 and the Japanese Earth Resource Satellite JERS-1. Mosaics of ERS tandem interferometric coherence and JERS backscattering coefficient show the wealth of information contained in these data but they also show large differences in radar response between neighbouring images. To create one homogeneous forest map, adaptive methods which are able to account for brightness changes due to environmental effects were required. In this paper an adaptive empirical model to determine growing stock volume classes using the ERS tandem coherence and the JERS backscatter data is described. For growing stock volume classes up to 80 m3/ha, accuracies of over 80% are achieved for over a hundred ERS frames at a spatial resolution of 50 m. 相似文献
137.
138.
Simulating deformable objects based on physical laws has become the most popular technique for modeling textiles, skin, or volumetric soft objects like human tissue. The physical model leads to an ordinary differential equation. Recently, several approaches to fast algorithms have been proposed.In this work, more profound numerical background about numerical stiffness is provided. Stiff equations impose stability restrictions on a numerical integrator. Some one-step and multistep methods with adequate stability properties are presented. For an efficient implementation, the inexact Newton method is discussed. Applications to 2D and 3D elasticity problems show that the discussed methods are faster and give higher-quality solutions than the commonly used linearized Euler method. 相似文献
139.
Tim Weitzel Daniel Beimborn Wolfgang König 《Information Systems and E-Business Management》2003,1(2):189-211
Networks utilizing modern communication technologies can offer competitive advantages to those using them wisely. But due
to the existence of network effects, planning and operating cooperation networks is difficult. In this paper, the strategic
situation of individual agents deciding on network participation is analysed. A systematic equilibrium analysis using computer-based
simulations reveals principal solution scenarios for network agents and shows that network cooperation problems might frequently
be not as difficult to resolve as often feared. In particular, strategic situations are identified showing that a majority
of individuals might be better off getting the optimal solution from a central principal and that in many cases simple information
intermediation can solve the start-up problem notorious in network economics. 相似文献
140.
Carl L. Gardner Wolfgang Nonner Robert S. Eisenberg 《Journal of Computational Electronics》2004,3(1):25-31
The drift-diffusion (Poisson-Nernst-Planck) model is applied to ionic channels in biological membranes plus surrounding solution baths. Simulations of the K channel in KCl solutions using the TRBDF2 method are presented which show significant boundary layers at the ends of the channel. The computed current-voltage curve for the K channel shows excellent agreement with experimental measurements. 相似文献