全文获取类型
收费全文 | 27296篇 |
免费 | 3514篇 |
国内免费 | 2879篇 |
专业分类
电工技术 | 2001篇 |
技术理论 | 3篇 |
综合类 | 3200篇 |
化学工业 | 634篇 |
金属工艺 | 583篇 |
机械仪表 | 1619篇 |
建筑科学 | 1372篇 |
矿业工程 | 500篇 |
能源动力 | 369篇 |
轻工业 | 383篇 |
水利工程 | 384篇 |
石油天然气 | 684篇 |
武器工业 | 298篇 |
无线电 | 6071篇 |
一般工业技术 | 1751篇 |
冶金工业 | 834篇 |
原子能技术 | 59篇 |
自动化技术 | 12944篇 |
出版年
2024年 | 142篇 |
2023年 | 337篇 |
2022年 | 705篇 |
2021年 | 751篇 |
2020年 | 929篇 |
2019年 | 708篇 |
2018年 | 783篇 |
2017年 | 882篇 |
2016年 | 978篇 |
2015年 | 1197篇 |
2014年 | 1897篇 |
2013年 | 1846篇 |
2012年 | 2238篇 |
2011年 | 2220篇 |
2010年 | 1883篇 |
2009年 | 1963篇 |
2008年 | 2076篇 |
2007年 | 2215篇 |
2006年 | 1893篇 |
2005年 | 1733篇 |
2004年 | 1368篇 |
2003年 | 1157篇 |
2002年 | 837篇 |
2001年 | 652篇 |
2000年 | 547篇 |
1999年 | 381篇 |
1998年 | 283篇 |
1997年 | 232篇 |
1996年 | 166篇 |
1995年 | 132篇 |
1994年 | 130篇 |
1993年 | 74篇 |
1992年 | 51篇 |
1991年 | 38篇 |
1990年 | 42篇 |
1989年 | 32篇 |
1988年 | 23篇 |
1987年 | 9篇 |
1986年 | 17篇 |
1985年 | 16篇 |
1984年 | 20篇 |
1983年 | 18篇 |
1982年 | 14篇 |
1981年 | 14篇 |
1980年 | 8篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1973年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
73.
Users expect applications to successfully cope with the expansion of information as necessitated by the continuous inclusion of novel types of content. Given that such content may originate from ‘not‐seen thus far’ data collections and/or data sources, the challenging issue is to achieve the return of investment on existing services, adapting to new information without changing existing business‐logic implementation. To address this need, we introduce DOLAR (Data Object Language And Runtime), a service‐neutral framework which virtualizes the information space to avoid invasive, time‐consuming, and expensive source‐code extensions that frequently break applications. Specifically, DOLAR automates the introduction of new business‐logic objects in terms of the proposed virtual ‘content objects’. Such user‐specified virtual objects align to storage artifacts and help realize uniform ‘store‐to‐user’ data flows atop heterogeneous sources, while offering the reverse ‘user‐to‐store’ flows with identical effectiveness and ease of use. In addition, the suggested virtual object composition schemes help decouple business logic from any content origin, storage and/or structural details, allowing applications to support novel types of items without modifying their service provisions. We expect that content‐rich applications will benefit from our approach and demonstrate how DOLAR has assisted in the cost‐effective development and gradual expansion of a production‐quality digital library. Experimentation shows that our approach imposes minimal overheads and DOLAR‐based applications scale as well as any underlying datastore(s). Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
74.
Generating quadrilateral meshes is a highly non-trivial task, as design decisions are frequently driven by specific application demands. Automatic techniques can optimize objective quality metrics, such as mesh regularity, orthogonality, alignment and adaptivity; however, they cannot make subjective design decisions. There are a few quad meshing approaches that offer some mechanisms to include the user in the mesh generation process; however, these techniques either require a large amount of user interaction or do not provide necessary or easy to use inputs. Here, we propose a template-based approach for generating quad-only meshes from triangle surfaces. Our approach offers a flexible mechanism to allow external input, through the definition of alignment features that are respected during the mesh generation process. While allowing user inputs to support subjective design decisions, our approach also takes into account objective quality metrics to produce semi-regular, quad-only meshes that align well to desired surface features. 相似文献
75.
Jinzhong Yang 《Pattern recognition letters》2011,32(7):910-918
This paper reviews the TPS-RPM algorithm (Chui and Rangarajan, 2003) for robustly registering two sets of points and demonstrates from a theoretical point of view its inherent limited performance when outliers are present in both point sets simultaneously. A double-sided outlier handling approach is proposed to overcome this limitation with a rigorous mathematical proof as the underlying theoretical support. This double-sided outlier handling approach is proved to be equivalent to the original formulation of the point matching problem. For a practical application, we also extend the TPS-RPM algorithms to non-rigid image registration by registering two sets of sparse features extracted from images. The intensity information of the extracted features are incorporated into feature matching in order to reduce the impact from outliers. Our experiments demonstrate the double-sided outlier handling approach and the efficiency of intensity information in assisting outlier detection. 相似文献
76.
YUAN Min 《数字社区&智能家居》2008,(34)
文章阐述了防火墙的基本原理、特点和功能,并通过实例实现基于Linux系统环境下,使用防火墙的方法。 相似文献
77.
张仰森 《计算机工程与设计》2001,22(5):36-38,42
自动声讯服务日益成为信息查询或传递的一条重要途径,文中介绍了支票挂失查询语音服务系统的功能,结构以及系统设计中 音卡编程的状态轮询方法和数据库的操作方法。 相似文献
78.
Richard E. Overill 《Computers and the Humanities》1993,27(2):105-110
In music analysis it is a common requirement to search a musical score for occurrences of a particular musical motif and its variants. This tedious and time-consuming task can be carried out by computer, using one of several models to specify which variants are to be included in the search. The question arises: just how many variants must be explicitly considered? The answer has a profound effect on the computer time needed. In this paper, recurrence relations and closed form analytic expressions are derived for the run time complexity of two models of fuzzy pattern matching for use in music analysis; each model assumes the existence of an atomic exact pattern matching operation. The formulae so obtained are evaluated and tabulated as a function of their independent parameters. These results enable a priori estimates to be made of the relative run times of different music searches performed using either model. This is illustrated by applying the results to an actual musical example.Richard E. Overill, BSc, PhD, C.Math, FIMA, C.Eng, MBCS, MIEE, is Lecturer in Computer Science at King's College London. His research includes the design, analysis, and practical implementation of algorithms on supercomputers. He has also given lecture-recitals on the keyboard music of the Tudor composers Thomas Tallis (1985), John Blitheman (1991), and William Byrd (1993). 相似文献
79.