全文获取类型
收费全文 | 6232篇 |
免费 | 898篇 |
国内免费 | 763篇 |
专业分类
电工技术 | 114篇 |
技术理论 | 1篇 |
综合类 | 550篇 |
化学工业 | 78篇 |
金属工艺 | 66篇 |
机械仪表 | 358篇 |
建筑科学 | 142篇 |
矿业工程 | 25篇 |
能源动力 | 30篇 |
轻工业 | 48篇 |
水利工程 | 19篇 |
石油天然气 | 28篇 |
武器工业 | 25篇 |
无线电 | 710篇 |
一般工业技术 | 392篇 |
冶金工业 | 247篇 |
原子能技术 | 7篇 |
自动化技术 | 5053篇 |
出版年
2024年 | 15篇 |
2023年 | 131篇 |
2022年 | 177篇 |
2021年 | 268篇 |
2020年 | 245篇 |
2019年 | 216篇 |
2018年 | 194篇 |
2017年 | 226篇 |
2016年 | 311篇 |
2015年 | 310篇 |
2014年 | 391篇 |
2013年 | 346篇 |
2012年 | 331篇 |
2011年 | 343篇 |
2010年 | 270篇 |
2009年 | 327篇 |
2008年 | 394篇 |
2007年 | 339篇 |
2006年 | 350篇 |
2005年 | 322篇 |
2004年 | 271篇 |
2003年 | 218篇 |
2002年 | 218篇 |
2001年 | 185篇 |
2000年 | 191篇 |
1999年 | 146篇 |
1998年 | 135篇 |
1997年 | 130篇 |
1996年 | 107篇 |
1995年 | 135篇 |
1994年 | 113篇 |
1993年 | 85篇 |
1992年 | 93篇 |
1991年 | 71篇 |
1990年 | 45篇 |
1989年 | 43篇 |
1988年 | 27篇 |
1987年 | 15篇 |
1986年 | 24篇 |
1985年 | 27篇 |
1984年 | 20篇 |
1983年 | 11篇 |
1982年 | 15篇 |
1981年 | 7篇 |
1980年 | 11篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1975年 | 5篇 |
排序方式: 共有7893条查询结果,搜索用时 15 毫秒
1.
In this paper, we strive to propose a self-interpretable framework, termed PrimitiveTree, that incorporates deep visual primitives condensed from deep features with a conventional decision tree, bridging the gap between deep features extracted from deep neural networks (DNNs) and trees’ transparent decision-making processes. Specifically, we utilize a codebook, which embeds the continuous deep features into a finite discrete space (deep visual primitives) to distill the most common semantic information. The decision tree adopts the spatial location information and the mapped primitives to present the decision-making process of the deep features in a tree hierarchy. Moreover, the trained interpretable PrimitiveTree can inversely explain the constituents of the deep features, highlighting the most critical and semantic-rich image patches attributing to the final predictions of the given DNN. Extensive experiments and visualization results validate the effectiveness and interpretability of our method. 相似文献
2.
Biologically inspired design (BID) is one of the common methods for product design. To solve the problem of inaccurate acquisition of inspirational creatures due to the lack of user perception preference analysis, a data-driven intelligent service model for BID considering user perception needs is proposed based on Kansei engineering. Firstly, by extracting the perceptual features of creatures from the semantic source elements of products through mapping and encodes them, we proposed a data acquisition method based on intuitionistic fuzzy sets considering different customer preference distributions, bridging the gap caused by the asymmetry between designers and users. Secondly, the functional relationship between biometric features and user-perceived attributes is identified and predicted, and a predictive model of biodata considering user preferences is obtained by multiple linear regression analysis. Finally, based on the data clustering and reorganization theory to understand the organization and dynamics of the database, the construction of a BID library was completed, and the design resources in the library were used as analyzed knowledge for designers to plan design activities. Taking the bionic design of a UAV product as an example, a prototype of a computer-aided design service system was developed based on the theory proposed in the article, and the analyzed knowledge was used to improve the efficiency and science of the design, effectively verifying the usefulness of this study for design. To a certain extent, this study addresses the problem of cognitive limitations of designers and cognitive differences between designers and users, promotes the application of bioinspiration in product design, and improves the marketability of design solutions. 相似文献
3.
We propose a general framework to study the relationship between the price of a painting and its color‐related attributes. To this end we focus on four key aspects: dominant colors, features of the color palette, color harmony, and color emotions. We demonstrate the usefulness of this approach with an example based on Mark Rothko's post‐1950 paintings (the “rectangular” series), and auction data from the 1994 to 2018 period. We identify two distinct price‐color regimes in Rothko's market: (a) [1994‐2005], a period in which prices are explained mainly by the growing popularity of the artist regardless of the color attributes of the paintings sold; and (b) [2006‐2018], a period in which color‐related attributes explain most of the prices. Furthermore, we find that in this second period, the dominant colors and the diversity of the color palette, are by far the most relevant attributes that influence the price; color harmony and color emotions hold almost no explanatory power during this period. Finally, we propose a new metric based on the Herfindahl Index to describe color diversity; this metric seems to be promising at characterizing the effect of the color palette on the price of a painting. 相似文献
4.
5.
Andrés Mario Zervigón 《History of Photography》2019,43(2):130-143
For decades now, Douglas Crimp’s landmark 1980 essay ‘The Photographic Activity of Postmodernism’ has shaped our understanding of modernism’s aftermath, at least as it unfolded in North America and Western Europe. Less remembered, however, is the degree to which the procedures of disjunction, copying, appropriation, and outright theft that he highlighted were epitomised not just by contemporary photography, but by photomontage in particular. This article recovers the debates that led critics such as Crimp, Abigail Solomon-Godeau, Christopher Phillips, Benjamin Buchloh and others to turn to photomontage as one of their principal objects of concern in what became known as the postmodern critique of photography. Why was montage tasked to perform this critical function, particularly by people around the journal October who had not otherwise devoted the balance of their writing to photography’s history? The article suggests that these men and women, along with the contemporary artists they foregrounded, manifested what Mary Anne Doane has called a ‘desire for signification’, a reaction in the late 1970s against the mute theatricality of minimalist and conceptual art. Photomontage reintroduced representation to contemporary art and to the canon of art history. But unlike the reemerging illusionism in painting that also manifested this desire, montage guarded against an uncomplicated realism by highlighting and critiquing operations of representation in a manner that painting no longer could. 相似文献
6.
针对新闻文本领域,该文提出一种基于查询的自动文本摘要技术,更加有针对性地满足用户信息需求。根据句子的TF-IDF、与查询句的相似度等要素,计算句子权重,并根据句子指示的时间给定不同的时序权重系数,使得最近发生的新闻内容具有更高的权重,最后使用最大边界相关的方法选择摘要句。通过与基于TF-IDF、Text-Rank、LDA等六种方法的对比,该摘要方法ROUGE评测指标上优于其他方法。从结合评测结果及摘要示例可以看出,该文提出的方法可以有效地从新闻文档集中摘取核心信息,满足用户查询内容的信息需求。 相似文献
7.
Numerical simulation techniques such as Finite Element Analyses are essential in today's engineering design practices. However, comprehensive knowledge is required for the setup of reliable simulations to verify strength and further product properties. Due to limited capacities, design-accompanying simulations are performed too rarely by experienced simulation engineers. Therefore, product models are not sufficiently verified or the simulations lead to wrong design decisions, if they are applied by less experienced users. This results in belated redesigns of already detailed product models and to highly cost- and time-intensive iterations in product development.Thus, in order to support less experienced simulation users in setting up reliable Finite Element Analyses, a novel ontology-based approach is presented. The knowledge management tools developed on the basis of this approach allow an automated acquisition and target-oriented provision of necessary simulation knowledge. This knowledge is acquired from existing simulation models and text-based documentations from previous product developments by Text and Data Mining. By offering support to less experienced simulation users, the presented approach may finally lead to a more efficient and extensive application of reliable FEA in product development. 相似文献
8.
特征表示是图像识别和分类的基础,视觉词袋是一种图像的特征表示方法。分析现有视觉词典构建方法的不足,提出一种新的视觉词典构建方法。首先利用梯度方差把特征矢量分为光滑类和边缘类,然后分别针对不同类别的特征矢量进行视觉词典的构建,最后根据两类视觉词典生成视觉词袋。图像分类实验表明,提出的新方法能提高分类准确率。 相似文献
9.
现阶段的语义解析方法大部分都基于组合语义,这类方法的核心就是词典。词典是词汇的集合,词汇定义了自然语言句子中词语到知识库本体中谓词的映射。语义解析一直面临着词典中词汇覆盖度不够的问题。针对此问题,该文在现有工作的基础上,提出了基于桥连接的词典学习方法,该方法能够在训练中自动引入新的词汇并加以学习,为了进一步提高新学习到的词汇的准确度,该文设计了新的词语—二元谓词的特征模板,并使用基于投票机制的核心词典获取方法。该文在两个公开数据集(WebQuestions和Free917)上进行了对比实验,实验结果表明,该文方法能够学习到新的词汇,提高词汇的覆盖度,进而提升语义解析系统的性能,特别是召回率。 相似文献
10.