全文获取类型
收费全文 | 18049篇 |
免费 | 1411篇 |
国内免费 | 23篇 |
专业分类
电工技术 | 188篇 |
综合类 | 15篇 |
化学工业 | 4743篇 |
金属工艺 | 195篇 |
机械仪表 | 489篇 |
建筑科学 | 742篇 |
矿业工程 | 29篇 |
能源动力 | 542篇 |
轻工业 | 3517篇 |
水利工程 | 148篇 |
石油天然气 | 63篇 |
无线电 | 1343篇 |
一般工业技术 | 3149篇 |
冶金工业 | 754篇 |
原子能技术 | 96篇 |
自动化技术 | 3470篇 |
出版年
2024年 | 45篇 |
2023年 | 222篇 |
2022年 | 450篇 |
2021年 | 683篇 |
2020年 | 503篇 |
2019年 | 522篇 |
2018年 | 718篇 |
2017年 | 731篇 |
2016年 | 868篇 |
2015年 | 650篇 |
2014年 | 921篇 |
2013年 | 1620篇 |
2012年 | 1476篇 |
2011年 | 1476篇 |
2010年 | 1018篇 |
2009年 | 992篇 |
2008年 | 1030篇 |
2007年 | 896篇 |
2006年 | 707篇 |
2005年 | 513篇 |
2004年 | 490篇 |
2003年 | 411篇 |
2002年 | 416篇 |
2001年 | 235篇 |
2000年 | 210篇 |
1999年 | 178篇 |
1998年 | 178篇 |
1997年 | 141篇 |
1996年 | 124篇 |
1995年 | 118篇 |
1994年 | 104篇 |
1993年 | 87篇 |
1992年 | 63篇 |
1991年 | 44篇 |
1990年 | 37篇 |
1989年 | 44篇 |
1988年 | 38篇 |
1987年 | 26篇 |
1986年 | 36篇 |
1985年 | 47篇 |
1984年 | 45篇 |
1983年 | 25篇 |
1982年 | 38篇 |
1981年 | 37篇 |
1980年 | 28篇 |
1979年 | 37篇 |
1978年 | 23篇 |
1977年 | 22篇 |
1976年 | 19篇 |
1973年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Vicente Rodríguez Montequín Francisco Ortega Fernández Nicolás Abajo de Martínez Juan Antonio González Rodríguez 《JOM Journal of the Minerals, Metals and Materials Society》2002,54(7):46-50
This research summary discusses the application of neural networks, evolutionary strategies, and other artificial intelligence
techniques in the modeling and optimization of the models used for temperature, rolling force, and torque calculation in heavy
plate milling. 相似文献
32.
33.
34.
35.
Rui A. S. Lapa José L. F. C. Lima 《Journal of Automated Methods and Management in Chemistry》1991,13(3):119-122
The construction of a microcomputer-controlled electrode switch for
use in potentiometric determinations is described. This can be coupled to most of the analytical equipment usually found in laboratories, to enable a setting up of automatic systems capable of performing sequential determinations with several ion-selective
electrodes. The assessment of its analytical usage and behaviour are discussed. 相似文献
36.
The Steady radial distribution of chemical species in a wire‐to‐cylinder ozone generator filled with pure oxygen has been computed by applying four different plasma chemistry models of increasing complexity. The most complete model considers ten species (e, O2 +, O2 ?, O3 ?, O?, O2, O2(1Δg), O2(1∑g +), O and O3) and 79 reactions, including ionization by electron impact, electron attachment and detachment, electron-ion recombination, charge transfer, etc. The chemical model is coupled with the electrical model through Poisson's equation. The spatially averaged ozone density has been computed as a function of the current intensity and compared with the experimental values obtained by UV spectroscopy. 相似文献
37.
André Revillon 《Journal of Coatings Technology》2002,74(930):55-63
This paper presents an academic analysis of recent progress and changes in polymer science. These changes influence the coatings
industry, as an answer to various constraints, such as enhanced applicability, quality certification, safety, and care of
environment. We do not focus on a specific topic but instead consider the basic concepts, the chemical advances in polymer
synthesis, and progress in fine characterization methods. Experimental results in polymerization, analysis, and new processes,
obtained in recent years, in the final period of my laboratory activity, are illustrated.
Presented at the 79th Annual Meeting of the Federation of Societies for Coatings Technology, in Atlanta, GA, Nov. 5–7, 2001.
200 Avenue Félix Faure, F-69003-Lyon, LMOPS, 69390 Vernaison on behalf of AFTPVA, France, email: arevillon@gonline.fr. 相似文献
38.
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
39.
Jose Ivan Escalante-Garcia Victor M. Palacios-Villanueva Alexander V. Gorokhovsky Guillermo Mendoza-Suárez Antonio F. Fuentes 《Journal of the American Ceramic Society》2002,85(7):1788-1792
Mortars of blast furnace slag blended with a geothermal silica waste at various replacement levels of 0%, 5%, 10%, 15%, and 20% were cured for up to 90 days. The binder was activated by 6 wt% Na2 O equivalent of sodium hydroxide. Lime was added as an activating agent and also to promote pozzolanic reaction with the silica. It was found that the presence of the silica waste increased the reactivity of the cementitious materials, as measured by means of nonevaporable water. The compressive strength was increased in the presence of the silica, except at the highest replacement level of 20%, the optimum silica replacement was that of 5%–10%. The microstructures of blended slag showed less porosity than those of neat slag mortars. The lime was completely consumed after 90 days of hydration. 相似文献
40.
Design optimization of 3D steel structures: Genetic algorithms vs. classical techniques 总被引:1,自引:0,他引:1
María Belén Prendes Gero Antonio Bello García 《Journal of Constructional Steel Research》2006,62(12):1303-1309
In this paper an elitist genetic algorithm (GA) developed by the authors is compared with common commercial solutions for complex structural optimization. After its prior validation on two-dimensional (2D) structures, the GA was tuned and improved in order to obtain structural elements with minimum weights that satisfy the ultimate limit states of the applicable building code. Subsequently, the same spatial structures were optimized using a commercial structural analysis program. Finally, the cost and weight improvements obtained using the GA, although at a higher computational cost, are discussed. 相似文献