全文获取类型
收费全文 | 5585篇 |
免费 | 200篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 139篇 |
综合类 | 13篇 |
化学工业 | 1426篇 |
金属工艺 | 117篇 |
机械仪表 | 104篇 |
建筑科学 | 431篇 |
矿业工程 | 10篇 |
能源动力 | 123篇 |
轻工业 | 753篇 |
水利工程 | 36篇 |
石油天然气 | 13篇 |
无线电 | 288篇 |
一般工业技术 | 921篇 |
冶金工业 | 650篇 |
原子能技术 | 58篇 |
自动化技术 | 711篇 |
出版年
2022年 | 44篇 |
2021年 | 70篇 |
2020年 | 56篇 |
2019年 | 58篇 |
2018年 | 67篇 |
2017年 | 85篇 |
2016年 | 114篇 |
2015年 | 137篇 |
2014年 | 149篇 |
2013年 | 250篇 |
2012年 | 227篇 |
2011年 | 243篇 |
2010年 | 209篇 |
2009年 | 224篇 |
2008年 | 219篇 |
2007年 | 251篇 |
2006年 | 202篇 |
2005年 | 203篇 |
2004年 | 184篇 |
2003年 | 126篇 |
2002年 | 137篇 |
2001年 | 111篇 |
2000年 | 100篇 |
1999年 | 77篇 |
1998年 | 89篇 |
1997年 | 86篇 |
1996年 | 82篇 |
1995年 | 75篇 |
1994年 | 55篇 |
1993年 | 80篇 |
1992年 | 80篇 |
1991年 | 53篇 |
1990年 | 62篇 |
1989年 | 61篇 |
1987年 | 71篇 |
1986年 | 58篇 |
1985年 | 72篇 |
1984年 | 65篇 |
1983年 | 61篇 |
1982年 | 63篇 |
1981年 | 68篇 |
1980年 | 67篇 |
1979年 | 68篇 |
1978年 | 51篇 |
1977年 | 54篇 |
1976年 | 57篇 |
1975年 | 56篇 |
1974年 | 67篇 |
1973年 | 50篇 |
1970年 | 41篇 |
排序方式: 共有5793条查询结果,搜索用时 0 毫秒
81.
Optical and mechanical properties of RLVIP HfO2 films In this paper HfO2‐films were deposited on unheated fused silica, borosilicate glass, and silicon wafer substrates by reactive low voltage ion plating (RLVIP). Optical film properties, i. e. refractive index and absorption as well as mechanical properties, particularly film stress, were investigated. Their dependence on deposition parameters, i. e. arc current and oxygen partial pressure was studied. The film refractive index was calculated from spectrophotometric measurements. The low absorption was determined by photothermal deflection spectrometry. Stress measurements were performed by bending disc method with uncoated and coated silicon wafer substrates. 相似文献
82.
83.
Ralf KretzschmarAuthor VitaeNicolaos B. KarayiannisAuthor Vitae Hans RichnerAuthor Vitae 《Pattern recognition》2003,36(11):2699-2712
This paper presents the results of a study that relied on trainable neural network classifiers to identify and remove bird-contaminated data from wind measurements recorded by a 1290-MHz wind profiler. A wind profiler is a Doppler radar system measuring the three-dimensional wind field. Migrating birds crossing the radar beam can lead to erroneous wind observations. Bird removal was performed by training conventional feedforward neural networks (FFNNs) and quantum neural networks (QNNs) to identify and remove bird-contaminated data recorded by a 1290-MHz wind profiler. A series of experiments evaluated several sets of input features extracted from wind profiler data, various FFNNs and QNNs of different sizes, and criteria employed for identifying birds in wind profiler data. 相似文献
84.
Our general goal in this paper is to show how to implement in GAMS standard deterministic nonlinear macro models, and stochastic linear macro models with rational expectations. We will also present basic concepts on solution methods and policy analysis for these kinds of models. As a practical illustration, we will use some well known teaching and experimental models in the macroeconomic literature. 相似文献
85.
This paper presents the combined use of meta-modelling and graph grammars for the generation of visual modelling tools for simulation formalisms. In meta-modelling, formalisms are described at a meta-level. This information is used by a meta-model processor to generate modelling tools for the described formalisms. We combine meta-modelling with graph grammars to extend the model manipulation capabilities of the generated modelling tools: edit, simulate, transform into another formalism, optimize and generate code. We store all (meta-)models as graphs, and thus, express model manipulations as graph grammars.We present the design and implementation of these concepts in AToM3 (A_To_ol for M_ulti-formalism, M_eta-M_odelling). AToM3 supports modelling of complex systems using different formalisms, all meta-modelled in their own right. Models in different formalisms may be transformed into a single common formalism for further processing. These transformations are specified by graph grammars. Mosterman and Vangheluwe [18] introduced the term multi-paradigm modelling to denote the combination of multiple formalisms, multiple abstraction levels, and meta-modelling. As an example of multi-paradigm modelling we present a meta-model for the Object-Oriented Continuous Simulation Language OOCSMP, in which we combine ideas from UML class diagrams (to express the OOCSMP model structure), Causal Block Diagrams (CBDs), and Statecharts (to specify the methods of the OOCSMP classes). A graph grammar is able to generate OOCSMP code, and then a compiler for this language (C-OOL) generates Java applets for the simulation execution. 相似文献
86.
The Treaty of the European Coal and Steel Community (ECSC), which expired in 2002, states in its Article 55 to promote technical and economic research with respect to the production and growing application of coal and steel. The results of funded research projects shall be made available to all representatives and partners concerned. For the European steel industry Article 55 was the basis for building up a steel research programme covering topics from raw materials to steel application and instigated a European network of researchers from the steel industry, research institutes and universities. On the basis of these research and development activities carried out by the ECSC steel research, the iron and steel industry has shown important advances in technology and environmental compatibility. Furthermore, the ECSC steel research has contributed to nearly all important technological developments. The main objective of the ECSC steel Research and Technology Development (RTD) programme was to sustain and develop the Community steel industry's competitiveness. The following report describes fundamental developments and activities within the framework of ECSC research with particular respect to hot metal production in the last 15 years. 相似文献
87.
Hans Bjrkman 《Creativity & Innovation Management》2004,13(2):97-108
Sif – a Swedish national trade union for white‐collar workers in Industry – has recognized the importance of enhancing its service innovation processes through careful listening to its members. This article will discuss the Design Dialogue Group (DDG) methodology that has been developed through collaborative research between Sif and the Fenix Research Program, in order to enhance group creativity and organizational learning. The emphasis of this paper is restricted to the issue of enhancing group creativity, and literature and empirical data will be used in order to discuss the factors enabling and restraining creativity. The major assumption behind this study is that many factors behind group creativity can be controlled. Thus, a careful design of the group creativity process would increase the likelihood for success since measures to enhance creative behaviours and to avoid pitfalls can be planned and/or taken by a group moderator. In short, the aims of this study are twofold: (1) to relate prior research contributions to DDG experiences in order to augment our understanding concerning factors enhancing and threatening creativity in DDG settings and (2) to systematize these findings into a set of proposed design principles related to domain‐relevant skills, creativity‐related processes, and task motivation. These propositions concern the recruitment of participants, group characteristics, and group processes. 相似文献
88.
Results from wear studies in repetitive impact sliding are described in this paper. The material pair studied consisted of steel CPM-10V (specimen) (where CPM denotes crucible particle metallurgy) and 17-4 precipitationhardened (PH) steel (counterface) with transverse sliding velocities of 4 and 8 m s?1. By means of scanning electron microscopy, energy-dispersive analysis of X-rays and X-ray diffraction methods it is shown that the wear is due to a material transport of the counterface 17-4 PH steel to the CPM-10V surface. In the wear process, a change in microhardness of the counterface substrate is apparent, and X-ray diffraction of debris confirms the presence of transformed metal. These products include γ-Fe together with trace amounts of α-Fe2O3; however, virtually no carbide from the CPM-10V steel was detected. 相似文献
89.
Multi-photon excitation in a time-of-flight mass spectrometer (TOF-MS) is shown to lead to threshold ions with defined internal energy. A powerful technique for the production of threshold ions is based on the excitation of high long-lived Rydberg states embedded in the ionization continuum. The Rydberg molecules are separated with suitable separation techniques from ions produced by a direct multi-photon ionization process. Finally, the ionization of the Rydberg molecules in a delayed pulsed electric field leads to threshold ions. This work reviews several separation techniques, and reports on applications of threshold ionization for investigation of the structure, energetics, and dynamics of neutral molecules, molecular cations, and cluster cations. 相似文献