全文获取类型
收费全文 | 56704篇 |
免费 | 6335篇 |
国内免费 | 1970篇 |
专业分类
电工技术 | 2732篇 |
综合类 | 4425篇 |
化学工业 | 10587篇 |
金属工艺 | 5545篇 |
机械仪表 | 2793篇 |
建筑科学 | 6777篇 |
矿业工程 | 987篇 |
能源动力 | 8705篇 |
轻工业 | 3111篇 |
水利工程 | 1121篇 |
石油天然气 | 2380篇 |
武器工业 | 363篇 |
无线电 | 1931篇 |
一般工业技术 | 6695篇 |
冶金工业 | 3662篇 |
原子能技术 | 1119篇 |
自动化技术 | 2076篇 |
出版年
2024年 | 170篇 |
2023年 | 752篇 |
2022年 | 1437篇 |
2021年 | 1811篇 |
2020年 | 1868篇 |
2019年 | 1480篇 |
2018年 | 1367篇 |
2017年 | 1614篇 |
2016年 | 1915篇 |
2015年 | 1953篇 |
2014年 | 3398篇 |
2013年 | 3503篇 |
2012年 | 3879篇 |
2011年 | 4216篇 |
2010年 | 3153篇 |
2009年 | 3232篇 |
2008年 | 2610篇 |
2007年 | 3641篇 |
2006年 | 3320篇 |
2005年 | 2879篇 |
2004年 | 2562篇 |
2003年 | 2249篇 |
2002年 | 2143篇 |
2001年 | 1656篇 |
2000年 | 1396篇 |
1999年 | 1158篇 |
1998年 | 946篇 |
1997年 | 803篇 |
1996年 | 691篇 |
1995年 | 576篇 |
1994年 | 483篇 |
1993年 | 390篇 |
1992年 | 326篇 |
1991年 | 224篇 |
1990年 | 189篇 |
1989年 | 191篇 |
1988年 | 125篇 |
1987年 | 104篇 |
1986年 | 92篇 |
1985年 | 62篇 |
1984年 | 101篇 |
1983年 | 71篇 |
1982年 | 77篇 |
1981年 | 22篇 |
1980年 | 21篇 |
1979年 | 16篇 |
1978年 | 9篇 |
1959年 | 33篇 |
1955年 | 8篇 |
1951年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 765 毫秒
141.
Yahia Lebbah 《Artificial Intelligence》2002,139(1):109-132
Search algorithms for solving Numeric CSPs (Constraint Satisfaction Problems) make an extensive use of filtering techniques. In this paper1 we show how those filtering techniques can be accelerated by discovering and exploiting some regularities during the filtering process. Two kinds of regularities are discussed, cyclic phenomena in the propagation queue and numeric regularities of the domains of the variables. We also present in this paper an attempt to unify numeric CSPs solving methods from two distinct communities, that of CSP in artificial intelligence, and that of interval analysis. 相似文献
142.
催化裂化与气体分离装置间热联合技术改造 总被引:1,自引:0,他引:1
利用催化裂化装置低温余热作为气体分离装置的重沸器热源,替代原来的气体分离塔重沸器加热蒸汽,合理利用了催化裂化装置的低温热,减少了催化裂化装置的循环冷却水用量及空冷用电量,又大幅降低了气体分离装置加热蒸汽量,取得了显著的节能效果及经济效益。 相似文献
143.
144.
40000m~3/h空分设备主换热器的设计及制造 总被引:1,自引:0,他引:1
通过对进口 4 0 0 0 0m3 /h空分设备主换热器进行结构分析及对比模拟计算 ,用国产传热翅片进行设计、采用真空钎焊工艺制造的主换热器 ,经并网运行 ,设计指标优于原空分设备 ,为今后成套大型空分设备板翅式换热器国产化设计、制造创造了条件。 相似文献
145.
146.
147.
148.
In various medium‐to‐large‐scale fire test equipments like the ISO room corner test (RC), and more recently, the single burning item test (SBI) the mass flow rate measurement of the combustion gases plays a key role in the determination of the heat‐release rate and smoke‐production rate. With the knowledge of the velocity profile and the temperature of the flow, the mass flow rate is obtained by measuring the velocity on the axis of the duct. This is done by means of a bi‐directional probe based on the pitot principle. However, due to the variation of the mean temperature and the temperature gradient in any cross section of the duct, introduced by ever changing combustion gas temperatures, the velocity nor the density profile are constant in time. This paper examines the resulting uncertainty on the mass flow rate. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
149.
Samuel L. Manzello Richard G. Gann Scott R. Kukuck Kuldeep Prasad Walter W. Jones 《火与材料》2007,31(5):297-310
A gypsum wall assembly was exposed to an intense real‐scale compartment fire. For the wall assembly, temperatures were measured at the exposed face, within the stud cavity, and at the unexposed face during the fire exposure. Total heat flux gauges were used to measure the temporal variation of the energy incident on the walls, and cameras, both visual and infrared, were used to image the unexposed face of the wall assembly during the fire exposure. The behaviour of the wall assembly under the fire load is discussed as are current model results for a simulation of the fire test. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
150.
Reviews the book, Forms of feeling: The heart of psychotherapy by Robert F. Hobson. Robert Hobson calls this book his autobiography as a therapist. As such it provides interesting glimpses into some of his more meaningful sessions with clients, illuminating his approach to therapy and enabling the reader to see a master therapist at work. Hobson also presents a new method of therapy, which he calls the conversational model. On this level, his book is considerably less satisfying. Hobson succinctly outlines the general principles of the conversational model and basic skills required of the therapist, but in so doing offers essentially little new information, however valid the points may be. According to Hobson, the conversational model is designed for clients whose problems arise from disturbances in their significant relationships, and those problems are best solved not by talking about them but by being in a relationship such as therapy that provides "a special kind of friendship." Hobson puts great stress on the use of metaphorical language in therapy and learning how to use the language of art as well as of science. He relies heavily on literary quotations, prefacing each section with one or two, and liberally interspersing many more within the pages of text. The net result is not so much illuminating as it is wearisome, and the general tone is slightly pretentious and, when Hobson addresses his "dear Reader" directly, somewhat condescending. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献