全文获取类型
收费全文 | 18551篇 |
免费 | 1936篇 |
国内免费 | 904篇 |
专业分类
电工技术 | 792篇 |
技术理论 | 1篇 |
综合类 | 1443篇 |
化学工业 | 255篇 |
金属工艺 | 144篇 |
机械仪表 | 720篇 |
建筑科学 | 7853篇 |
矿业工程 | 145篇 |
能源动力 | 122篇 |
轻工业 | 91篇 |
水利工程 | 69篇 |
石油天然气 | 199篇 |
武器工业 | 157篇 |
无线电 | 2730篇 |
一般工业技术 | 457篇 |
冶金工业 | 106篇 |
原子能技术 | 43篇 |
自动化技术 | 6064篇 |
出版年
2024年 | 102篇 |
2023年 | 418篇 |
2022年 | 585篇 |
2021年 | 667篇 |
2020年 | 758篇 |
2019年 | 545篇 |
2018年 | 350篇 |
2017年 | 341篇 |
2016年 | 321篇 |
2015年 | 473篇 |
2014年 | 1185篇 |
2013年 | 910篇 |
2012年 | 1242篇 |
2011年 | 1400篇 |
2010年 | 1095篇 |
2009年 | 1261篇 |
2008年 | 1328篇 |
2007年 | 1430篇 |
2006年 | 1196篇 |
2005年 | 1096篇 |
2004年 | 923篇 |
2003年 | 761篇 |
2002年 | 535篇 |
2001年 | 453篇 |
2000年 | 423篇 |
1999年 | 333篇 |
1998年 | 209篇 |
1997年 | 175篇 |
1996年 | 135篇 |
1995年 | 122篇 |
1994年 | 96篇 |
1993年 | 92篇 |
1992年 | 90篇 |
1991年 | 69篇 |
1990年 | 45篇 |
1989年 | 49篇 |
1988年 | 46篇 |
1987年 | 27篇 |
1986年 | 17篇 |
1985年 | 29篇 |
1984年 | 27篇 |
1983年 | 10篇 |
1982年 | 7篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1965年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
11.
12.
基于联系国内外智能交通系统研究的具体实际,提出了建立城市智能交通实验研究中心的设想,并结合一个集成了视频和线圈信息采集方式的实验研究中心简单设计方案,对其所具有的基本功能作了初步研究和探讨。该系统兼具促进交流和有关培训等社会职能,可以作为国家智能交通事业发展过程中一种特殊的示范工程。 相似文献
13.
Due to the demand for real time wavelet processors in applications such as video compression [1], Internet communications compression [2], object recognition [3], and numerical analysis, many architectures for the Discrete Wavelet Transform (DWT) systems have been proposed. This paper surveys the different approaches to designing DWT architectures. The types of architectures depend on whether the application is 1-D, 2-D, or 3-D, as well as the style of architecture: systolic, semi-systolic, folded, digit-serial, etc. This paper presents an overview and evaluation of the architectures based on the criteria of latency, control, area, memory, and number of multipliers and adders. This paper will give the reader an indication of the advantages and disadvantages of each design. 相似文献
14.
15.
高炉开炉装料计算工作繁琐、复杂,手工计算耗费时间长、容易出错,难以得到最佳方案,影响高炉顺利开炉。通过高炉开炉装料计算软件的开发实践,介绍了装料计算模型的建模步骤;讨论了软件的功能需求;阐述了选用三层网络结构的原因,从而描述了装料计算软件的设计方法。软件投入运行后,能够快速、准确地计算、分析开炉数据,取得了满意的效果。 相似文献
16.
17.
YT-1000型油压自动调速器在运行中不能维持正常油压、在不增加任何设备的情况下,只改动二次接线的处理方法,就能消除隐患、解决问题。 相似文献
18.
The cost of maintaining a software system over a long period of time far exceeds its initial development cost. Much of the maintenance cost is attributed to the time required by new developers to understand legacy systems. High-level structural information helps maintainers navigate through the numerous low-level components and relations present in the source code. Modularization tools can be used to produce subsystem decompositions from the source code but do not typically produce high-level architectural relations between the newly found subsystems. Controlling subsystem interactions is one important way in which the overall complexity of software maintenance can be reduced.We have developed a tool, called ARIS (Architecture Relation Inference System), that enables software engineers to define rules and relations for regulating subsystem interactions. These rules and relations are called Interconnection Styles and are definedusing a visual notation. The style definition is used by our tool to infer subsystem-level relations in designs being reverse engineered from source code.In this paper we describe our tool and its underlying techniques and algorithms. Using a case study, we describe how ARIS is used to reverse engineer high-level structural information from a real application. 相似文献
19.
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
20.
Transmission of signals, whether on-chip or off-chip, places severe constraints on timing and extracts a large price in energy. New silicon device technologies, such as back-plane CMOS, provide a programmable and adaptable threshold voltage as an additional tool that can be used for low power design. We show that one particularly desirable use of this freedom is energy-efficient high-speed transmission across long interconnects using multi-valued encoding. Our multi-valued CMOS circuits take advantage of the threshold voltage control of the transistors, by using the signal-voltage-to-threshold-voltage span, in order to make area-efficient implementations of 4-PAM (pulse amplitude modulation) transceivers operating at high speed. In a comparison of a variety of published technologies, for signal transmission with interconnects of 10-15 mm length, we show up to 50% improvement in energy for on-chip signal transmission over binary encoding together with higher limits for operating speeds without a penalty in circuit noise margin. 相似文献