全文获取类型
收费全文 | 5899篇 |
免费 | 104篇 |
国内免费 | 85篇 |
专业分类
电工技术 | 42篇 |
综合类 | 128篇 |
化学工业 | 667篇 |
金属工艺 | 301篇 |
机械仪表 | 502篇 |
建筑科学 | 970篇 |
矿业工程 | 143篇 |
能源动力 | 259篇 |
轻工业 | 159篇 |
水利工程 | 47篇 |
石油天然气 | 224篇 |
武器工业 | 51篇 |
无线电 | 180篇 |
一般工业技术 | 995篇 |
冶金工业 | 538篇 |
原子能技术 | 48篇 |
自动化技术 | 834篇 |
出版年
2024年 | 6篇 |
2023年 | 88篇 |
2022年 | 102篇 |
2021年 | 148篇 |
2020年 | 124篇 |
2019年 | 111篇 |
2018年 | 113篇 |
2017年 | 143篇 |
2016年 | 157篇 |
2015年 | 168篇 |
2014年 | 279篇 |
2013年 | 321篇 |
2012年 | 283篇 |
2011年 | 501篇 |
2010年 | 361篇 |
2009年 | 338篇 |
2008年 | 357篇 |
2007年 | 345篇 |
2006年 | 273篇 |
2005年 | 248篇 |
2004年 | 246篇 |
2003年 | 220篇 |
2002年 | 176篇 |
2001年 | 102篇 |
2000年 | 127篇 |
1999年 | 144篇 |
1998年 | 129篇 |
1997年 | 111篇 |
1996年 | 65篇 |
1995年 | 60篇 |
1994年 | 57篇 |
1993年 | 39篇 |
1992年 | 26篇 |
1991年 | 21篇 |
1990年 | 20篇 |
1989年 | 17篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有6088条查询结果,搜索用时 15 毫秒
21.
The twinning of YBa2Cu3O7 (YBCO) thin films with c-axis orientation on (001) MgO, (001) SrTiO3, (012) LaAlO3, (110) NdGaO3 and (001) NdGaO3 substrates, prepared by laser ablation, has been examined using a combination of and θ/2θ scans at a four-circle diffractometer. On all substrates, except for (001) NdGaO3, the tetragonal to orthorhombal phase transition results in four different orientations of YBCO twins relating to the substrate. On (001) NdGaO3 only two different twin orientations, accompanied by a slight lattice monoclinization, has been observed. 相似文献
22.
首先在结构上创造了新型螺栓、螺母和一套崭新的安装机。在主机上去掉了精密、复杂、昂贵的机器人或机械手,改用结构简单的集成齿轮机构,以实现同步旋拧功能;运用现代流体传动与控制的理论,建立流本控制的数学模型和传递函数,从而实现了4个同步安装的效果。 相似文献
23.
A New Approach to Abstract Syntax with Variable Binding 总被引:1,自引:1,他引:0
The permutation model of set theory with atoms (FM-sets), devised by Fraenkel and Mostowski in the 1930s, supports notions
of ‘name-abstraction’ and ‘fresh name’ that provide a new way to represent, compute with, and reason about the syntax of formal
systems involving variable-binding operations. Inductively defined FM-sets involving the name-abstraction set former (together
with Cartesian product and disjoint union) can correctly encode syntax modulo renaming of bound variables. In this way, the
standard theory of algebraic data types can be extended to encompass signatures involving binding operators. In particular,
there is an associated notion of structural recursion for defining syntax-manipulating functions (such as capture avoiding
substitution, set of free variables, etc.) and a notion of proof by structural induction, both of which remain pleasingly
close to informal practice in computer science.
Received October 2000 / Accepted in revised form April 2001 相似文献
24.
The research literature has seen a number of studies aimed at understanding customer attitudes towards banking technologies, and thereby providing implications for developmental planning and marketing. However, even though banking technologies have a significant amount of information systems (IS) component to them, there is a paucity of research that considers them from the IS perspective. In this paper, we fill this gap by considering three constructs, namely usefulness, ease of use and usage, that are all rooted in the IS literature. We study user’s perceptions of these constructs, as well as the relationships among them, for both online and telephone banking. 相似文献
25.
黄怀德 《导弹与航天运载技术》1996,(1)
重点介绍有关H—Ⅱ运载火箭(以下简称H—Ⅱ)的一些动力学课题的研究状况。其中,重要的动力学课题有全箭振动、POGO、防液体晃动、分离动力学试验、动力学环境试验等。针对这些动力学课题,日本有关部门已研究多年,既作了充分的地面试验,又进行了有效的工程应用研究,最终保证了H—Ⅱ的首次飞行成功。 相似文献
26.
Rose Challenger Desmond J. Leach Christopher B. Stride Chris W. Clegg 《人机工程学与制造业中的人性因素》2012,22(3):197-212
Clegg and Spencer's (2007) model of job design synthesizes and extends recent conceptions of the job design process by incorporating variables such as knowledge, motivation, and trust into a cyclical and dynamic system. The objective of this study was to examine the sequential organization of variables that comprise the model, as a basis from which to justify further investigations of the model's dynamic properties. Data were collected via questionnaires from 432 participants in two work organizations. Results obtained from structural equation modeling are broadly supportive of the proposed relationships between the variables. Implications of this initial study for future research and practice are discussed. © 2011 Wiley Periodicals, Inc. 相似文献
27.
28.
Despite the successes in the last two decades, the state-of-the-art face detectors still have problems in dealing with images in the wild due to large appearance variations. Instead of leaving appearance variations directly to statistical learning algorithms, we propose a hierarchical part based structural model to explicitly capture them. The model enables part subtype option to handle local appearance variations such as closed and open month, and part deformation to capture the global appearance variations such as pose and expression. In detection, candidate window is fitted to the structural model to infer the part location and part subtype, and detection score is then computed based on the fitted configuration. In this way, the influence of appearance variation is reduced. Besides the face model, we exploit the co-occurrence between face and body, which helps to handle large variations, such as heavy occlusions, to further boost the face detection performance. We present a phrase based representation for body detection, and propose a structural context model to jointly encode the outputs of face detector and body detector. Benefit from the rich structural face and body information, as well as the discriminative structural learning algorithm, our method achieves state-of-the-art performance on FDDB, AFW and a self-annotated dataset, under wide comparisons with commercial and academic methods. 相似文献
29.
Jason Hochreiter Zhongkai HanSyed Zain Masood Spencer FonteMarshall Tappen 《Image and vision computing》2014
In this paper, we propose an album-oriented face-recognition model that exploits the album structure for face recognition in online social networks. Albums, usually associated with pictures of a small group of people at a certain event or occasion, provide vital information that can be used to effectively reduce the possible list of candidate labels. We show how this intuition can be formalized into a model that expresses a prior on how albums tend to have many pictures of a small number of people. We also show how it can be extended to include other information available in a social network. Using two real-world datasets independently drawn from Facebook, we show that this model is broadly applicable and can significantly improve recognition rates. 相似文献
30.
Recently, many local-feature based methods have been proposed for feature learning to obtain a better high-level representation of human behavior. Most of the previous research ignores the structural information existing among local features in the same video sequences, while it is an important clue to distinguish ambiguous actions. To address this issue, we propose a Laplacian group sparse coding for human behavior representation. Unlike traditional methods such as sparse coding, our approach prefers to encode a group of relevant features simultaneously and meanwhile allow as less atoms as possible to participate in the approximation so that video-level sparsity is guaranteed. By incorporating Laplacian regularization the method is capable to ensure the similar approximation of closely related local features and the structural information is successfully preserved. Thus, a compact but discriminative human behavior representation is achieved. Besides, the objective of our model is solved with a closed-form solution, which reduces the computational cost significantly. Promising results on several popular benchmark datasets prove the efficiency and effectiveness of our approach. 相似文献