全文获取类型
收费全文 | 22637篇 |
免费 | 5718篇 |
国内免费 | 894篇 |
专业分类
电工技术 | 1959篇 |
综合类 | 2613篇 |
化学工业 | 2436篇 |
金属工艺 | 487篇 |
机械仪表 | 2038篇 |
建筑科学 | 828篇 |
矿业工程 | 117篇 |
能源动力 | 2296篇 |
轻工业 | 634篇 |
水利工程 | 366篇 |
石油天然气 | 282篇 |
武器工业 | 228篇 |
无线电 | 1978篇 |
一般工业技术 | 764篇 |
冶金工业 | 397篇 |
原子能技术 | 156篇 |
自动化技术 | 11670篇 |
出版年
2023年 | 89篇 |
2022年 | 346篇 |
2021年 | 342篇 |
2020年 | 368篇 |
2019年 | 428篇 |
2018年 | 602篇 |
2017年 | 532篇 |
2016年 | 619篇 |
2015年 | 467篇 |
2014年 | 3829篇 |
2013年 | 2614篇 |
2012年 | 3473篇 |
2011年 | 3843篇 |
2010年 | 3389篇 |
2009年 | 3015篇 |
2008年 | 1253篇 |
2007年 | 458篇 |
2006年 | 357篇 |
2005年 | 399篇 |
2004年 | 413篇 |
2003年 | 355篇 |
2002年 | 262篇 |
2001年 | 254篇 |
2000年 | 211篇 |
1999年 | 170篇 |
1998年 | 156篇 |
1997年 | 151篇 |
1996年 | 134篇 |
1995年 | 125篇 |
1994年 | 96篇 |
1993年 | 81篇 |
1992年 | 78篇 |
1991年 | 61篇 |
1990年 | 54篇 |
1989年 | 62篇 |
1988年 | 47篇 |
1987年 | 36篇 |
1986年 | 20篇 |
1985年 | 11篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 578 毫秒
11.
12.
本文描述在Unix环境下开发的通用绘图软件NuSlide中的图形用户界面的设计思想和实际方法。其特点是基子面向对象的技术,提供多窗口、菜单驱动、选择面板、键盘输入等多种才法。该图形用户界面具有灵活性、可扩充性和易使用性。 相似文献
13.
本文通过分析现有工程图纸扫描图象的识别与理解系统,提出了表面粗造度的自动识别算法,从而弥补了以往系统的不足,基于图形约束的表面粗造度整体识别算法符合技术人员的读图规律,处理速度快,可靠性高,该算法已在微机上调试成功。 相似文献
14.
We present methods to generate rendering sequences for triangle meshes which preserve mesh locality as much as possible. This is useful for maximizing vertex reuse when rendering the mesh using a FIFO vertex buffer, such as those available in modern 3D graphics hardware. The sequences are universal in the sense that they perform well for all sizes of vertex buffers, and generalize to progressive meshes. This has been verified experimentally. 相似文献
15.
16.
The requirements on an object-oriented DBMS for management of information in a large, complex enterprise are presented. These requirements aid in the achievement of an environment characterized by data sharing, open architectures, application and data portability, and assurance of data integrity. They were defined from the point of view of a user of the DBMS; therefore they describe the expected functionality of the DBMS and do not specify the method of implementation to achieve this functionality. They encompass requirements on the data model, query and data manipulation languages, the system architecure, interfaces to the system, change management, and transaction management. 相似文献
17.
18.
Human facial gestures often exhibit such natural stochastic variations as how often the eyes blink, how often the eyebrows and the nose twitch, and how the head moves while speaking. The stochastic movements of facial features are key ingredients for generating convincing facial expressions. Although such small variations have been simulated using noise functions in many graphics applications, modulating noise functions to match natural variations induced from the affective states and the personality of characters is difficult and not intuitive. We present a technique for generating subtle expressive facial gestures (facial expressions and head motion) semi‐automatically from motion capture data. Our approach is based on Markov random fields that are simulated in two levels. In the lower level, the coordinated movements of facial features are captured, parameterized, and transferred to synthetic faces using basis shapes. The upper level represents independent stochastic behavior of facial features. The experimental results show that our system generates expressive facial gestures synchronized with input speech. 相似文献
19.
Accurate and efficient vectorization of line drawings is essential for any higher level processing in document analysis and
recognition systems. In spite of the prevalence of vectorization and line detection methods, no standard for their performance
evaluation protocol exists. We propose a protocol for evaluating both straight and circular line extraction to help compare,
select, improve, and even design line detection algorithms to be incorporated into line drawing recognition and understanding
systems. The protocol involves both positive and negative sets of indices, at pixel and vector levels. Time efficiency is
also included in the protocol. The protocol may be extended to handle lines of any shape as well as other classes of graphic
objects. 相似文献
20.
The object-oriented approach has recently received much attention in MIS development. However, as yet little research has been reported on task analysis in the object-oriented paradigm. This paper describes an object-oriented method for task analysis. Three fundamental types of objects (task, user, and interface) engaged in task analysis are described. The association between these objects is then built through identifying the messages between the objects. A practical application of this method shows that it is useful for the analysis and design of a human-computer interface. 相似文献