全文获取类型
收费全文 | 3983篇 |
免费 | 84篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 42篇 |
综合类 | 4篇 |
化学工业 | 830篇 |
金属工艺 | 94篇 |
机械仪表 | 84篇 |
建筑科学 | 160篇 |
矿业工程 | 12篇 |
能源动力 | 90篇 |
轻工业 | 320篇 |
水利工程 | 33篇 |
石油天然气 | 12篇 |
武器工业 | 2篇 |
无线电 | 365篇 |
一般工业技术 | 624篇 |
冶金工业 | 739篇 |
原子能技术 | 41篇 |
自动化技术 | 618篇 |
出版年
2021年 | 40篇 |
2020年 | 33篇 |
2019年 | 39篇 |
2018年 | 66篇 |
2017年 | 48篇 |
2016年 | 58篇 |
2015年 | 45篇 |
2014年 | 102篇 |
2013年 | 218篇 |
2012年 | 140篇 |
2011年 | 196篇 |
2010年 | 131篇 |
2009年 | 139篇 |
2008年 | 189篇 |
2007年 | 148篇 |
2006年 | 147篇 |
2005年 | 135篇 |
2004年 | 109篇 |
2003年 | 103篇 |
2002年 | 112篇 |
2001年 | 69篇 |
2000年 | 72篇 |
1999年 | 77篇 |
1998年 | 178篇 |
1997年 | 109篇 |
1996年 | 93篇 |
1995年 | 78篇 |
1994年 | 55篇 |
1993年 | 66篇 |
1992年 | 43篇 |
1991年 | 54篇 |
1990年 | 45篇 |
1989年 | 39篇 |
1988年 | 42篇 |
1987年 | 42篇 |
1986年 | 62篇 |
1985年 | 53篇 |
1984年 | 48篇 |
1983年 | 44篇 |
1982年 | 40篇 |
1981年 | 53篇 |
1980年 | 45篇 |
1979年 | 43篇 |
1978年 | 41篇 |
1977年 | 44篇 |
1976年 | 40篇 |
1975年 | 34篇 |
1973年 | 25篇 |
1972年 | 25篇 |
1971年 | 25篇 |
排序方式: 共有4070条查询结果,搜索用时 46 毫秒
41.
Krieshok Thomas S.; Arnold John J.; Kuperman Bernard D.; Schmitz Nancy K. 《Canadian Metallurgical Quarterly》1988,35(2):211
We respond to Cochran's critique of our 1986 study, which was in part a replication of Cochran's original grid methodology for the study of career values. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
42.
This paper presents a new massively parallel MIMD architecture, halfway between the Connection Machine and hypercubes based on 32-bit processors. It is built from specific 8-bit processors arranged in a 2-D grid and communicating by message transfers. We discuss the communication problems, the instruction set of the basic processing unit, the programmation of the whole array and the use of a high level data-flow language. 相似文献
43.
Paul Camion Bernard Courteau Philippe Delsarte 《Applicable Algebra in Engineering, Communication and Computing》1992,2(3):147-162
The concept of the combinatorial matrix of an unrestricted code and the notion of anr-partition design admitted by a code are introduced and discussed in detail. The theory includes a characterization of completely regular codes, and a combinatorial interpretation of the fact that the distinct rows of the distance distribution matrix of a code are linearly independent. In general, it is possible to compute the distance distribution matrix of any code admitting a given partition design by solving a well-defined system of linear equations; this is an efficient technique provided the number of classes in the partition is relatively small. 相似文献
44.
André Girard Pierre Dominique Lansard Bernard Liau Anne Marie Mongeon Jean Luc Thibault 《电信纪事》1991,46(5-6):335-350
Classical hierarchical routing in telephone networks is extended to a wider class called out-of-chain routing in such a way that some useful properties of hierarchical routing are retained. This new routing pattern offers more potential paths than the fixed hierarchical one and can be introduced as a dynamic routing where the fixed alternate sequences change at some predetermined instants during the day. The effect of this new routing pattern on the network performances is examined. The main topic of this paper is to present heuristic methods used to optimise such routings in large networks. We show on artificial networks that the throughput of a given network can be significantly improved by suitable routing choices. We demonstrate that the integration of routing changes within a multihour dimensioning process is possible but the lack of realistic data does not permit at this time to quantify the value of routing optimization on real networks. 相似文献
45.
Vision and navigation for the Carnegie-Mellon Navlab 总被引:7,自引:0,他引:7
Thorpe C. Hebert M.H. Kanade T. Shafer S.A. 《IEEE transactions on pattern analysis and machine intelligence》1988,10(3):362-373
A distributed architecture articulated around the CODGER (communication database with geometric reasoning) knowledge database is described for a mobile robot system that includes both perception and navigation tools. Results are described for vision and navigation tests using a mobile testbed that integrates perception and navigation capabilities that are based on two types of vision algorithms: color vision for road following, and 3-D vision for obstacle detection and avoidance. The perception modules are integrated into a system that allows the vehicle to drive continuously in an actual outdoor environment. The resulting system is able to navigate continuously on roads while avoiding obstacles 相似文献
46.
Sagaspe Patricia; Charles André; Taillard Jacques; Bioulac Bernard; Philip Pierre 《Canadian Metallurgical Quarterly》2003,57(4):265
The literature contains inconsistent data on the effects of acute sleep deprivation on the superior cognitive functions. The primary purpose of this study is to determine the effectiveness of inhibition, one of the functions of the working memory executive centre (EC), over an extended, 36-hour waking period. Inhibition is a cognitive mechanism whereby individuals ignore non-relevant information recorded in their working memory. We also tested the effects of a 36- hour period of acute sleep deprivation on simple reaction time. Twelve young, healthy volunteers (M=21.5 years, ?=2.3) performed a random generation task involving letters and a simple reaction time psychomotor test over four sessions held at 10-hour intervals. Each participant was assigned a "constant routine." Participants were kept awake in a prone position within a room whose environment was held strictly constant (light, noise, temperature, meals, etc.). This control procedure provided assurance that any variation in participant performance was solely caused by sleep deprivation. The random generation task, nearly two minutes in length, consisted in verbally producing a sequence of 100 letters in a random fashion (i.e. by inhibiting, for example, alphabetical order) and by keeping to a set rhythm... (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
47.
Bernard Grabot Laurent Geneste Arnaud Dupeux 《Journal of Intelligent Manufacturing》1994,5(5):303-313
Most of the available industrial schedulers are based on a simulation approach using dispatching rules. These rules are often dedicated to the satisfaction of a single performance criterion, and are used whatever the characteristics of the workshop or of the set of jobs. An approach which allows one to bring in compromises between rules is set out in this paper. These compromises can be parametered in accordance with the objectives of the workshop and the characteristics of the jobs in order to introduce some reactivity in the decision system. Three ways to set up the parameters are compared: experimental design, fuzzy expert system and neural network. The method allowing one to define compromises can be implemented on each scheduler that uses a simulation approach. Tests have been made with an industrial scheduler called SIPAPLUS, the results of which are developed in this paper. 相似文献
48.
49.
Clusters and grids of workstations provide available resources for data mining processes. To exploit these resources, new distributed algorithms are necessary, particularly concerning the way to distribute data and to use this partition. We present a clustering algorithm dubbed Progressive Clustering that provides an “intelligent” distribution of data on grids. The usefulness of this algorithm is shown for several distributed datamining tasks. 相似文献
50.
We compare, in this paper, the far field radiated by two fractal distributions of current. The first one is obtained by a fractal cut following the Cantor arrangement, the second one keeps the length of each previous current element, but modifies the distance between the elements which is now taken as a constant. We establish the analytical formulations of the far field at any step n of the Cantor set. Then, we extract the array factor and we analyse and compare the following properties : convergence of the radiation pattern, wide of the main lobe, side lobes level and directivity. 相似文献