全文获取类型
收费全文 | 49843篇 |
免费 | 5309篇 |
国内免费 | 4053篇 |
专业分类
电工技术 | 4084篇 |
技术理论 | 12篇 |
综合类 | 6410篇 |
化学工业 | 3671篇 |
金属工艺 | 608篇 |
机械仪表 | 2145篇 |
建筑科学 | 2935篇 |
矿业工程 | 1356篇 |
能源动力 | 2025篇 |
轻工业 | 1030篇 |
水利工程 | 1238篇 |
石油天然气 | 819篇 |
武器工业 | 930篇 |
无线电 | 6800篇 |
一般工业技术 | 2777篇 |
冶金工业 | 1975篇 |
原子能技术 | 422篇 |
自动化技术 | 19968篇 |
出版年
2024年 | 198篇 |
2023年 | 647篇 |
2022年 | 1210篇 |
2021年 | 1389篇 |
2020年 | 1533篇 |
2019年 | 1152篇 |
2018年 | 1029篇 |
2017年 | 1347篇 |
2016年 | 1563篇 |
2015年 | 1744篇 |
2014年 | 3301篇 |
2013年 | 3176篇 |
2012年 | 3901篇 |
2011年 | 3926篇 |
2010年 | 3081篇 |
2009年 | 3335篇 |
2008年 | 3478篇 |
2007年 | 3800篇 |
2006年 | 3410篇 |
2005年 | 3036篇 |
2004年 | 2665篇 |
2003年 | 2316篇 |
2002年 | 1713篇 |
2001年 | 1389篇 |
2000年 | 1095篇 |
1999年 | 749篇 |
1998年 | 551篇 |
1997年 | 439篇 |
1996年 | 359篇 |
1995年 | 293篇 |
1994年 | 259篇 |
1993年 | 195篇 |
1992年 | 150篇 |
1991年 | 124篇 |
1990年 | 78篇 |
1989年 | 80篇 |
1988年 | 71篇 |
1987年 | 53篇 |
1986年 | 45篇 |
1985年 | 50篇 |
1984年 | 60篇 |
1983年 | 43篇 |
1982年 | 21篇 |
1981年 | 14篇 |
1980年 | 19篇 |
1979年 | 16篇 |
1977年 | 8篇 |
1965年 | 10篇 |
1964年 | 11篇 |
1961年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
带类型的λ-演算是一个逻辑系统,它可以作为程序语言的基础.Plotkin所引进的PCF就是这样一类程序语言.Plotkin构造了PCF的一个模型,然后讨论与这个模型相关的指称语义和操作语义之间的配合问题──简单配合和完全配合.本文利用Scott引进的信息系统概念构造PCF的另一种模型,并证明与这个模型对应的指称语义与操作语义是完全配合的. 相似文献
102.
103.
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
104.
主要介绍了自动化部近几年来在科技创新和管理方面的工作经验,如围绕莱钢生产建设全力推进技术创新;以“数字莱钢”建设为目标,加快推进莱钢信息化建设,所有这些都为莱钢提供了强有力的自动化信息化技术支撑。 相似文献
105.
SHARED: An information model for cooperative product development 总被引:6,自引:0,他引:6
One fundamental issue in developing collaborative engineering systems is the representation of product information which supports communication and coordination. This product information includes not only the geometric and physical properties of the product and its parts, but also information about functions, constraints and the design rationale. In this paper, we describe an information model, SHARED, which was developed for encoding product information in DICE, a distributed and integrated environment for computer-aided engineering. SHARED provides multiple levels of both functional and geometric abstractions, multiple views and techniques for maintaining consistency between the various abstractions and views. These elements are essential for a good representation model of product information. The use of the SHARED model is illustrated through an example, depicting the various representations of a product as it evolves through the design process. The SHARED model has been implemented over a distributed OODBMS as a toolkit/framework for developing environments which need to model, manipulate and communicate product information between distributed cooperating applications, while supporting coordination between them. 相似文献
106.
Hironori Oda 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1995,63(3):223-228
Fluorans are given considerable attention as functional dyes for heat-and/or pressure-sensitive recording media. Numerous potential metal complexes were synthesised to prolong the life of coloured species. The protecting effect of these compounds against the photofading was examined on cellulose. It was found that the zinc or nickel salts of 3,5-dihydroxy-2-naphthoic acid and its derivatives can be applied as effective stabilisers against the fading of fluoran dyes. 相似文献
107.
108.
针对信息化时代企业情报工作面临的新课题,结合本企业情况,从成为企业技术创新的加油站、成为职工素质提高的资源库、成为企业获取和分析竞争环境的侦察兵、成为企业信息安全的保护伞等方面论述了企业情报工作与时俱进等理念和方法。 相似文献
109.
房地产开发企业会计核算问题探讨 总被引:1,自引:0,他引:1
本文就房地产开发企业会计核算的现状及特点进行了分析,并提出了完善房地产开发企业会计核算规范的对策。 相似文献
110.
Joel 《Journal of Parallel and Distributed Computing》2005,65(12):1601-1606
Lee and Batcher have designed networks that efficiently merge k separately provided sorted sequences of known lengths totalling n. We show that the design is still possible, and in fact easier to describe, if we do not make use of the lengths, or even the directions of monotonicity, of the individual sequences—the sequences can be provided in a single undelimited concatenation of length n. The depth of the simplest resulting network to sort sequences that are “k-tonic” and of length n is , generalizing Batcher's 1968 results for the extreme values of k (k=2 corresponding to merging, and k=n/2 corresponding to general sorting).The exposition is self-contained and can serve even as an introduction to sorting networks and Batcher's results. 相似文献