全文获取类型
收费全文 | 28456篇 |
免费 | 3149篇 |
国内免费 | 2342篇 |
专业分类
电工技术 | 3198篇 |
技术理论 | 3篇 |
综合类 | 3410篇 |
化学工业 | 1015篇 |
金属工艺 | 668篇 |
机械仪表 | 2823篇 |
建筑科学 | 792篇 |
矿业工程 | 480篇 |
能源动力 | 615篇 |
轻工业 | 257篇 |
水利工程 | 522篇 |
石油天然气 | 377篇 |
武器工业 | 239篇 |
无线电 | 2666篇 |
一般工业技术 | 2183篇 |
冶金工业 | 377篇 |
原子能技术 | 152篇 |
自动化技术 | 14170篇 |
出版年
2024年 | 104篇 |
2023年 | 282篇 |
2022年 | 477篇 |
2021年 | 603篇 |
2020年 | 697篇 |
2019年 | 707篇 |
2018年 | 653篇 |
2017年 | 929篇 |
2016年 | 1045篇 |
2015年 | 1201篇 |
2014年 | 1649篇 |
2013年 | 2044篇 |
2012年 | 1928篇 |
2011年 | 2003篇 |
2010年 | 1513篇 |
2009年 | 1683篇 |
2008年 | 1765篇 |
2007年 | 1970篇 |
2006年 | 1700篇 |
2005年 | 1514篇 |
2004年 | 1337篇 |
2003年 | 1144篇 |
2002年 | 997篇 |
2001年 | 845篇 |
2000年 | 743篇 |
1999年 | 620篇 |
1998年 | 500篇 |
1997年 | 518篇 |
1996年 | 419篇 |
1995年 | 380篇 |
1994年 | 357篇 |
1993年 | 274篇 |
1992年 | 261篇 |
1991年 | 176篇 |
1990年 | 143篇 |
1989年 | 132篇 |
1988年 | 117篇 |
1987年 | 73篇 |
1986年 | 66篇 |
1985年 | 55篇 |
1984年 | 66篇 |
1983年 | 40篇 |
1982年 | 41篇 |
1981年 | 26篇 |
1980年 | 29篇 |
1979年 | 33篇 |
1978年 | 12篇 |
1977年 | 25篇 |
1976年 | 17篇 |
1975年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
介绍了大型机床地坑移动盖板的一般设计思想,根据机床原有功能和结构特点,设计兼顾防尘防屑和美观大方两大特点的活动盖板,为同类设计提供一些参考。 相似文献
92.
Saumya K. Debray 《Software》1993,23(12):1337-1360
Janus is a language designed for distributed constraint programming. This paper describes QD-Janus, a sequential implementation of Janus in Prolog. The compiler uses a number of novel analyses and optimizations to improve the performance of the system. The choice of Prolog as the target language for a compiler, although unusual, is motivated by the following: (i) the semantic gap between Janus and Prolog is much smaller than that between Janus and, say, C or machine language—this simplifies the compilation process significantly, and makes it possible to develop a system with reasonable performance fairly quickly; (ii) recent progress in Prolog implementation techniques, and the development of Prolog systems whose speeds are comparable to those of imperative languages, indicates that the translation to Prolog need not entail a significant performance loss compared to native code compilers; and (iii) compilation to Prolog can benefit immediately from a significant body of work on, and implementations of, parallel Prolog systems. Our experience indicates that translation of logic programming languages to Prolog, accompanied by the development of good program analysis and optimization tools, is an effective way to quickly develop flexible and portable implementations with good performance and low cost. 相似文献
93.
Qidong Cao Mark A. Mcknew 《International Journal of Flexible Manufacturing Systems》1994,6(2):155-172
A new optimization model is discussed for the design of cellular manufacturing systems. It is based on an integer programming formulation that updates some other models by eliminating redundant machine assignment and cost coefficients dependent on cell configuration. To reduce computational burdens, a simplified integer programming model and a decomposition algorithm are proposed. Several computer solutions were performed to evaluate the performance of the new model. The computational results are discussed. 相似文献
94.
面向对象机器翻译知识库IMT—KB的设计与实现 总被引:1,自引:0,他引:1
机器翻译知识库是机译系统的重要组成部分,针对传统机译知识库的不足之处,本文提出一种面向对象的机译知识体系结构,同时给出这种具有层次性和模块性机译知识库的存储组织和管理机制。 相似文献
95.
This paper presents the development of an event-driven control architecture and its implementation in a physical simulator of a computerized manufacturing system using object-oriented techniques. The architecture was developed to improve the efficiency of handling concurrent control events in the DOS environment. In the implementation, the control system of the physical simulator consists of four distinct layers of control devices: a PC/386 computer, a microcontroller, I/O modules and the system's control devices such as motors, solenoids and sensors. A control program residing in the PC/386 coordinates system-level tasks such as event scheduling, while a BASIC program running on the microcontroller handles all low-level control tasks such as sensor monitoring and motion control. The concepts and developments presented in this paper should help in implementing an efficient control system for both CIM systems and their physical simulators. 相似文献
96.
David L. Spooner 《Journal of Intelligent Manufacturing》1994,5(1):13-21
A product database for a design and manufacturing enterprise serves as a repository for the data needed to manufacture a product. This paper discusses how an object-oriented persistent object manager named ROSE, under development at Rensselaer, has been used in the Rensselaer CIM program to develop a STEP/PDES-compliant product database for its research test bed. In so doing, it provides an overview of the requirements for a product database system in an integrated design and manufacturing facility, and it discusses how the chosen system meets these requirements. 相似文献
97.
We consider an extension of the functional programming language Standard ML with a modular structure based upon concepts in category theory such as categories, functors, natural transformations and adjunctions. In essence, we are following the categorical imperative of considering arrows as well as objects. This is intended to enforce a certain mathematical rigour on the programmer, so that the only programs that can be expressed are those with a categorical significance. The essentially algebraic nature of category theory means that we may generate equational correctness conditions for the modular structure of programs, thus separating the correctness of individual functions from that of modules. We describe this programming language, give examples of its use, and explain how it is implemented in a type system. 相似文献
98.
多版本软件通过设计相异性实现了软件容错。为了对这种方法进行研究,我们的课题实现了一个三版本软件系统,称之为SFTMP(SoftwareFault-TolerantMultiProcessor)。本文描述了SFTMP的硬件结构和软件执行支持环境,该环境包括同步、表决和监控功能、版本间的通讯及故障的恢复和重构。 相似文献
99.
Timo Knuutila 《Software》1992,22(3):209-221
This paper presents some basic programming strategies for Prolog programmers. The strategies are based on knowledge about the operational behaviour of the Warren Abstract Machine (WAM). The aim is to provide simple principles for making programs both faster and less space-consuming. The programming hints given are mostly local, i.e. only a single clause or procedure need be considered at a time. 相似文献
100.
This paper contributes to extend the minimax disparity to determine the ordered weighted averaging (OWA) model based on linear programming. It introduces the minimax disparity approach between any distinct pairs of the weights and uses the duality of linear programming to prove the feasibility of the extended OWA operator weights model. The paper finishes with an open problem. 相似文献