全文获取类型
收费全文 | 5048篇 |
免费 | 740篇 |
国内免费 | 679篇 |
专业分类
电工技术 | 113篇 |
技术理论 | 1篇 |
综合类 | 453篇 |
化学工业 | 89篇 |
金属工艺 | 64篇 |
机械仪表 | 309篇 |
建筑科学 | 133篇 |
矿业工程 | 25篇 |
能源动力 | 29篇 |
轻工业 | 41篇 |
水利工程 | 18篇 |
石油天然气 | 27篇 |
武器工业 | 25篇 |
无线电 | 711篇 |
一般工业技术 | 324篇 |
冶金工业 | 190篇 |
原子能技术 | 7篇 |
自动化技术 | 3908篇 |
出版年
2024年 | 36篇 |
2023年 | 128篇 |
2022年 | 173篇 |
2021年 | 264篇 |
2020年 | 242篇 |
2019年 | 208篇 |
2018年 | 201篇 |
2017年 | 227篇 |
2016年 | 302篇 |
2015年 | 284篇 |
2014年 | 340篇 |
2013年 | 294篇 |
2012年 | 270篇 |
2011年 | 268篇 |
2010年 | 197篇 |
2009年 | 229篇 |
2008年 | 278篇 |
2007年 | 238篇 |
2006年 | 247篇 |
2005年 | 234篇 |
2004年 | 218篇 |
2003年 | 164篇 |
2002年 | 163篇 |
2001年 | 140篇 |
2000年 | 152篇 |
1999年 | 106篇 |
1998年 | 98篇 |
1997年 | 108篇 |
1996年 | 81篇 |
1995年 | 92篇 |
1994年 | 84篇 |
1993年 | 60篇 |
1992年 | 72篇 |
1991年 | 59篇 |
1990年 | 36篇 |
1989年 | 32篇 |
1988年 | 21篇 |
1987年 | 12篇 |
1986年 | 20篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 2篇 |
排序方式: 共有6467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.
Yasoub Eghbali Mahmoud Ferdosizade Naeiny 《International Journal of Communication Systems》2020,33(14)
In this paper, an off‐grid direction of arrival (DoA) estimation method is proposed for wideband signals. This method is based on the sparse representation (SR) of the array covariance matrix. Similar to the time domain DoA estimation methods, the correlation function of the sources was assumed to be the same and known. A new measurement vector is obtained using the lower‐left triangular elements of the covariance matrix. The DoAs are estimated by quantizing the entire range of continuous angle space into discrete grid points. However, the exact DoAs may be located between two grid points; therefore, this estimation has errors. The accuracy of DoA estimation is improved by the minimization of the difference between the new measurement vector and its estimated values. Simulation results revealed that the proposed method can enhance the DoA estimation accuracy of wideband signals. 相似文献
3.
AbstractIndustry 4.0 aims at providing a digital representation of a production landscape, but the challenges in building, maintaining, optimizing, and evolving digital models in inter-organizational production chains have not been identified yet in a systematic manner. In this paper, various Industry 4.0 research and technical challenges are addressed, and their present scenario is discussed. Moreover, in this article, the novel concept of developing experience-based virtual models of engineering entities, process, and the factory is presented. These models of production units, processes, and procedures are accomplished by virtual engineering object (VEO), virtual engineering process (VEP), and virtual engineering factory (VEF), using the knowledge representation technique of Decisional DNA. This blend of the virtual and physical domains permits monitoring of systems and analysis of data to foresee problems before they occur, develop new opportunities, prevent downtime, and even plan for the future by using simulations. Furthermore, the proposed virtual model concept not only has the capability of Query Processing and Data Integration for Industrial Data but also real-time visualization of data stream processing. 相似文献
4.
A conceptualization of intended learning outcomes supporting self‐regulated learners in indicating learning paths
下载免费PDF全文
![点击此处可从《Journal of Computer Assisted Learning》网站下载免费的PDF全文](/ch/ext_images/free.gif)
P. Tangworakitthaworn L. Gilbert G.B. Wills 《Journal of Computer Assisted Learning》2015,31(5):393-404
Intended learning outcomes (ILOs) indicate what learners will be able to achieve after they are taught. Traditionally, ILOs are expressed as plain text or unstructured documents. What if all ILOs of a specific course of study can be conceptualized through a structured diagrammatic technique? It was hypothesized that learners can benefit from this conceptualization in learning, especially in self‐regulated learning. The aim of this study was to investigate whether the ILOs represented in unstructured or structured formats can facilitate learners to identify learning paths. The results revealed that the mean ratings of all learning paths were statistically significantly higher with structured ILOs. 相似文献
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
8.
9.
非线性扩频序列的三项式特性 总被引:5,自引:1,他引:4
讨论了三类非线性扩频序列(GMW序列、No序列和Kasami序列)的三项式特性,利用这三类序列的迹表示,证明了GMW序列、No序列和Kasami序列均具有正则三项式对。 相似文献
10.
Fertuck Eric A.; Bucci Wilma; Blatt Sidney J.; Ford Richard Q. 《Canadian Metallurgical Quarterly》2004,41(1):13
This study examined the relation between changes in clinical functioning and changes in verbal expression in 81 seriously disturbed and treatment-resistant young adults seen in a comprehensive, psychoanalytically oriented inpatient treatment. Clinical functioning was evaluated with a battery of clinical and social measures. Verbal representations were assessed using computer-assisted scoring of Thematic Apperception Test responses. Changes in the frequency of verbal content and style in the narratives of these patients covaried with changes in clinical functioning. Significantly different covariations of verbal and clinical change, particularly differences in covariates of referential activity, were found for patients with anaclitic versus introjective personality configurations. The implications of these findings for understanding and treating severe psychopathology are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献