全文获取类型
收费全文 | 329553篇 |
免费 | 28377篇 |
国内免费 | 16416篇 |
专业分类
电工技术 | 22493篇 |
技术理论 | 13篇 |
综合类 | 22585篇 |
化学工业 | 49476篇 |
金属工艺 | 20014篇 |
机械仪表 | 21194篇 |
建筑科学 | 23672篇 |
矿业工程 | 9478篇 |
能源动力 | 8551篇 |
轻工业 | 21756篇 |
水利工程 | 7280篇 |
石油天然气 | 17547篇 |
武器工业 | 3021篇 |
无线电 | 37137篇 |
一般工业技术 | 42539篇 |
冶金工业 | 17534篇 |
原子能技术 | 6662篇 |
自动化技术 | 43394篇 |
出版年
2024年 | 1525篇 |
2023年 | 4870篇 |
2022年 | 9874篇 |
2021年 | 13428篇 |
2020年 | 10074篇 |
2019年 | 8139篇 |
2018年 | 9714篇 |
2017年 | 11119篇 |
2016年 | 9950篇 |
2015年 | 12937篇 |
2014年 | 16556篇 |
2013年 | 19797篇 |
2012年 | 22317篇 |
2011年 | 23491篇 |
2010年 | 21123篇 |
2009年 | 20183篇 |
2008年 | 19915篇 |
2007年 | 18822篇 |
2006年 | 17243篇 |
2005年 | 13985篇 |
2004年 | 10166篇 |
2003年 | 9219篇 |
2002年 | 9096篇 |
2001年 | 8145篇 |
2000年 | 6813篇 |
1999年 | 5742篇 |
1998年 | 4161篇 |
1997年 | 3474篇 |
1996年 | 3141篇 |
1995年 | 2738篇 |
1994年 | 2272篇 |
1993年 | 1746篇 |
1992年 | 1617篇 |
1991年 | 1370篇 |
1990年 | 1329篇 |
1989年 | 1216篇 |
1988年 | 1040篇 |
1987年 | 938篇 |
1986年 | 852篇 |
1985年 | 753篇 |
1984年 | 738篇 |
1981年 | 708篇 |
1979年 | 761篇 |
1978年 | 786篇 |
1977年 | 748篇 |
1976年 | 765篇 |
1975年 | 721篇 |
1974年 | 726篇 |
1973年 | 728篇 |
1972年 | 707篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
魏巍 《重庆科技学院学报(社会科学版)》2008,(12)
缺乏有力的监督和制约机制是我国行政判决执行难的重要原因之一.主张赋予检察机关时行政诉讼执行环节实施法律监督的权利.从而有效防止执行程序违法.抑制怠于执行和拖延执行现象的发生.阐述了由检察机关实施监督的法理依据,介绍了检察监督的方式. 相似文献
84.
Yu. G. Volodin 《Thermal Engineering》2007,54(5):399-402
The results of experimental study of unsteady effects on local heat transfer coefficients caused by abruptly increasing of the gas flow temperature in the inlet section of a cylindrical channel are presented. 相似文献
85.
86.
Heidi Bernas Arie J. Plomp Johannes H. Bitter Dmitry Yu. Murzin 《Catalysis Letters》2008,120(1-2):8-13
The density functional theory (DFT/B3LYP) calculations were applied to investigate the interaction of a Pt6 particle with the ZSM-5 zeolite framework. The electronic structure of the metal particle is strongly affected by the interaction with basic framework oxygens and acid sites of the zeolite support. Adsorption on basic sites (Eads = 6 kcal/mol) favors the formation of the electron enriched metal cluster. Interaction of the platinum cluster with the acid site characterized by stabilization energy of 47 kcal/mol results in oxidation of the metal particle and suppression of Brønsted acidity of the support. The hypothesis is put forward that the oxidized platinum particle can function as an active site for the alkane isomerisation on platinum supported high silica zeolites. 相似文献
87.
S. M. Obraztsov G. A. Birzhevoi Yu. V. Konobeev V. A. Solov'ev O. S. Silkina 《Atomic Energy》2004,96(2):111-116
The results of a computational experiment with a neural-net model simulating the effect of the chemical composition on the plastic properties of ÉP-450 steel are presented. It is shown that computer-aided development of reactor steel with prescribed properties is, in principle, possible. 相似文献
88.
A. V. Zrodnikov G. I. Toshinskii O. G. Grigor'ev Yu. G. Dragunov V. S. Stepanov N. N. Klimov I. I. Kopytov V. N. Krushel'nitskii A. A. Grudakov 《Atomic Energy》2004,97(2):528-533
The results of development work on the SVBR-75/100 modular fast reactor cooled by lead–bismuth coolant are presented. The design is based on the experience gained operating reactors in nuclear-powered submarines. The SVBR-75/100 reactor is inherently safe because of its low power, the chemical inertness and high boiling point of the lead–bismuth coolant, and the integrated basin-type arrangement of the first-loop equipment. This eliminates the conflict between the safety and economic requirements that is characteristic of conventional-type reactors. The lower power makes it possible to build the reactor in a factory and deliver the reactor using any form of transportation to the nuclear power plant site. All safety systems operate passively. Most of these systems are used as normal-operating systems. This creates conditions for multipurpose applications of such reactor modules in developed and developing countries. 相似文献
89.
Age assessment and control of the reliability of the coolant flow-rate measurement system of the RBMK-1500 reactor at the Ignalina nuclear power plant are examined. A statistical analysis is made of the data obtained from measurements of the techanical characteristics of SHADR-32M flow meters. A mathematical model of the aging of flow meters and reliability estimates is constructed. A strategy is developed for replacing SHADR; this strategy makes it possible to support the required relaibility of the entire coolant flow-rate measurement system. 相似文献
90.
LaNiO3 was synthesized by sol-gel method in which lanthanum nitrate and nickel nitrate were used as start materials and citric acid was used as complex for gel formation.The precursor was dried and subsequently heated at elevated temperature to form the desired product.XRD analysis shows that pure LaNiO3 was synthesized.Electrical conductivity and electrochemical performance of the material were tested.The electrical conductivity decreases from 34.5that there are current peaks in the curve, which is the evidence of the electrochemical activity of LaNiO3. 相似文献