全文获取类型
收费全文 | 413篇 |
免费 | 8篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 95篇 |
金属工艺 | 15篇 |
机械仪表 | 9篇 |
建筑科学 | 9篇 |
矿业工程 | 1篇 |
能源动力 | 23篇 |
轻工业 | 10篇 |
石油天然气 | 7篇 |
无线电 | 33篇 |
一般工业技术 | 108篇 |
冶金工业 | 72篇 |
自动化技术 | 37篇 |
出版年
2023年 | 7篇 |
2022年 | 8篇 |
2021年 | 18篇 |
2020年 | 12篇 |
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 5篇 |
2015年 | 7篇 |
2014年 | 2篇 |
2013年 | 18篇 |
2012年 | 8篇 |
2011年 | 9篇 |
2010年 | 16篇 |
2009年 | 11篇 |
2008年 | 10篇 |
2007年 | 7篇 |
2006年 | 5篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2002年 | 8篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 21篇 |
1997年 | 27篇 |
1996年 | 21篇 |
1995年 | 20篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1966年 | 1篇 |
排序方式: 共有421条查询结果,搜索用时 15 毫秒
1.
2.
Adherent and pin-hole free amorphous Sb2Te3 thin films have been obtained by vacuum evaporation at substrate temperatures ≤25 °C. The films have been crystallized by thermal and laser annealing, and the crystallization processes monitored as a function of annealing temperature and laser scan speed. A comparative study of topography reveals disk-shaped crystallized areas in thermal crystallization and dendrite growth in the laser induced process. The crystallized films in both cases contain a single Sb2Te3 phase. Activation energy of 2 eV for crystallization, determined using differential scanning calorimetery indicates good room temperature stability of the amorphous states. 相似文献
3.
The methodology for developing intelligent integrated computer-aided design and manufacturing systems based on object-oriented principles is discussed. The ways in which the application of these principles affects the nature of these systems are reviewed. The implementation of an automated, intelligent, and flexible computer-integrated-manufacturing (CIM) system prototype using an object-oriented programming environment (Smalltalk-80, Version 4.0) is detailed. A CIM system includes CAD, a process planner, and an inspection planner. Each of these components is discussed individually 相似文献
4.
Dynamic mechanical test methods have been widely employed for investigating the structures and viscoelastic behavior of polymeric materials to determine their relevant stiffness and damping characteristics for various applications. Randomly oriented short banana/sisal hybrid fiber–reinforced polyester composites were prepared by keeping the volume ratio of banana and sisal 1 : 1 and the total fiber loading 0.40 volume fraction. Bilayer (banana/sisal), trilayer (banana/sisal/banana and sisal/banana/sisal), and intimate mix composites were prepared. The effect of layering pattern on storage modulus (E′), damping behavior (tan δ), and loss modulus (E″) was studied as a function of temperature and frequency. Bilayer composite showed high damping property while intimately mixed and banana/sisal/banana composites showed increased stiffness compared to the other pattern. The Arrhenius relationship has been used to calculate the activation energy of the glass transition of the composites. The activation energy of the intimately mixed composite was found to be the highest. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2168–2174, 2005 相似文献
5.
Good-quality diamond-like carbon films (6 at.% H2, 2400 kgf/mm2 microhardness, 2.7 eV bandgap, higly insulating) have been obtained by the DC glow discharge decomposition of acetylene. Mass spectroscopic thermal effusion measurements were carried out on the films deposited under different deposition conditions. Analyses of hydrogen in conjunction with hydrocarbon effusing species yield information on the microstructure and nature of C---H bonding configurations. It is shown to be a useful analytical tool to study hydrogenated amorphous carbon films of different microstructures varying from polymer-like to diamond-like. 相似文献
6.
Single point incremental forming: state-of-the-art and prospects 总被引:1,自引:0,他引:1
Joost R. Duflou Anne-Marie Habraken Jian Cao Rajiv Malhotra Markus Bambach Dave Adams Hans Vanhove Amirahmad Mohammadi Jack Jeswiet 《International Journal of Material Forming》2018,11(6):743-773
Incremental sheet metal forming in general and Single Point Incremental Forming (SPIF) specifically have gone through a period of intensive development with growing attention from research institutes worldwide. The result of these efforts is significant progress in the understanding of the underlying forming mechanisms and opportunities as well as limitations associated with this category of flexible forming processes. Furthermore, creative process design efforts have enhanced the process capabilities and process planning methods. Also, simulation capabilities have evolved substantially. This review paper aims to provide an overview of the body of knowledge with respect to Single Point Incremental Forming. Without claiming to be exhaustive, each section aims for an up-to-date state-of-the-art review with corresponding conclusions on scientific progress and outlook on expected further developments. 相似文献
7.
Using direct and indirect equilibration methods, the solubilities of iron in molten bismuth and those of bismuth in molten iron-carbon alloys have been measured over the temperature range 1473-1873 K. The Henrian behaviour of bismuth in molten ferrous alloys allows the calculation of its activity coefficient, which in turn facilitates modelling as a function of temperature and carbon content, using the unified interaction parameter formalism developed by Pelton and Bale. The modelling results generate the expression: . A model has also been developed expressing bismuth content in molten iron-carbon alloys as a function of temperature and composition: . 相似文献
8.
Empirical validation of software metrics used to predict software quality attributes is important to ensure their
practical relevance in software organizations. The aim of this work is to find the relation of object-oriented (OO) metrics
with fault proneness at different severity levels of faults. For this purpose, different prediction models have been developed
using regression and machine learning methods. We evaluate and compare the performance of these methods to find which method
performs better at different severity levels of faults and empirically validate OO metrics given by Chidamber and Kemerer.
The results of the empirical study are based on public domain NASA data set. The performance of the predicted models was evaluated
using Receiver Operating Characteristic (ROC) analysis. The results show that the area under the curve (measured from the
ROC analysis) of models predicted using high severity faults is low as compared with the area under the curve of the model
predicted with respect to medium and low severity faults. However, the number of faults in the classes correctly classified
by predicted models with respect to high severity faults is not low. This study also shows that the performance of machine
learning methods is better than logistic regression method with respect to all the severities of faults. Based on the results,
it is reasonable to claim that models targeted at different severity levels of faults could help for planning and executing
testing by focusing resources on fault-prone parts of the design and code that are likely to cause serious failures. 相似文献
9.
In this paper, a compact asymmetric coplanar strip (ACS)-fed printed monopole antenna for dual frequency operation is presented. The proposed antenna is composed of an ACS-fed monopole structure and two semi circle shaped radiating branches, which occupies a very small size of 13.4 × 22.7 mm2 including the ground plane. By properly selecting the length and position of these branches, two desired operating bands can be achieved and tuned independently. The simulated and measured return loss results shows that the proposed antenna can be used for long term evolution 2500 (2500–2690 MHz), WLAN 5.2 GHz (5.15–5.35 GHz)/5.8 GHz (5.725–5.825 GHz), WiMAX 5.5 GHz (5.28–5.85 GHz) and 4.9 GHz (4.94–4.99 GHz) public safety applications. The omnidirectional and bidirectional radiation pattern characteristics in H-plane and E-plane of the proposed antenna along with acceptable peak gain make the best suitable candidate for the above intended applications. 相似文献
10.
This paper develops a framework for the consideration of internal markets as an alternative to information systems (IS) outsourcing. It is based on an assessment of the pros and cons of both outsourcing and of insourcing based on the internal markets approach. It is formulated in terms of the operational, tactical, and strategic impacts of the choice among the alternatives. The framework, and the propositions that are developed from it, should be useful both for researchers, who can use it for developing testable research hypotheses, and for practitioners, who may use it as a basis for developing a comprehensive set of criteria for the evaluation of these sourcing options. 相似文献