全文获取类型
收费全文 | 1940篇 |
免费 | 91篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 15篇 |
综合类 | 1篇 |
化学工业 | 375篇 |
金属工艺 | 10篇 |
机械仪表 | 13篇 |
建筑科学 | 82篇 |
矿业工程 | 1篇 |
能源动力 | 48篇 |
轻工业 | 317篇 |
水利工程 | 24篇 |
石油天然气 | 7篇 |
无线电 | 91篇 |
一般工业技术 | 324篇 |
冶金工业 | 531篇 |
原子能技术 | 3篇 |
自动化技术 | 192篇 |
出版年
2023年 | 24篇 |
2022年 | 41篇 |
2021年 | 71篇 |
2020年 | 43篇 |
2019年 | 47篇 |
2018年 | 44篇 |
2017年 | 46篇 |
2016年 | 42篇 |
2015年 | 55篇 |
2014年 | 65篇 |
2013年 | 84篇 |
2012年 | 87篇 |
2011年 | 124篇 |
2010年 | 89篇 |
2009年 | 89篇 |
2008年 | 114篇 |
2007年 | 130篇 |
2006年 | 112篇 |
2005年 | 91篇 |
2004年 | 83篇 |
2003年 | 70篇 |
2002年 | 61篇 |
2001年 | 23篇 |
2000年 | 29篇 |
1999年 | 30篇 |
1998年 | 51篇 |
1997年 | 42篇 |
1996年 | 47篇 |
1995年 | 25篇 |
1994年 | 27篇 |
1993年 | 23篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1966年 | 2篇 |
排序方式: 共有2034条查询结果,搜索用时 15 毫秒
131.
Despite an increasing emphasis on the role of senior managementcognition in shaping organizational action, there have beenfew attempts to link top management mental models to strategicchoice in the face of discontinuous innovation. This paper uses23 years of data covering 15 major pharmaceutical firms to explorethe degree to which each firm's response to the revolution inbiotechnology was shaped by the senior team's recognition ofbiotechnology's importance. Controlling for a number of importantalternative explanations, we show that recognition may be animportant predictor of action, suggesting that cognition atthe most senior level can play a critical role in shaping establishedfirms' response to discontinuities. 相似文献
132.
Physical gaming is a genre of computer games that has recently been made available for the home. But what does it mean to bring games home that were originally designed for play in the arcade? This paper describes an empirical study that looks at physical gaming and how it finds its place in the home. We discuss the findings from this study by organizing them around four topics: the adoption of the game, its unique spatial needs, the tension between visibility and availability of the game, and what it means to play among what we describe as the gaming circle, or players and non-players alike. Finally, we discuss how physical gaming in the home surfaces questions and issues for householders and researchers around adoption, gender and both space and place. 相似文献
133.
Boye Sandra M.; Grant Rebecca J.; Tawfik Vivianne L. 《Canadian Metallurgical Quarterly》2007,121(3):550
The authors hypothesized that repeated rewarding electrical stimulation of the dorsal raphe can produce behavioral sensitization to psychostimulants. Groups of male rats were implanted with a stimulation electrode and preexposed to brain stimulation at parameters set to equate rewarding effectiveness across rats. Control groups were implanted with an electrode but never stimulated, or not implanted at all. Twenty-four hours after the 12th self-stimulation session, all groups were challenged with amphetamine (0.5 mg/kg, ip), nicotine (0.2 mg/kg, sc), or saline, and locomotor activity was measured for 1 hr. Locomotor responses to amphetamine and to nicotine were significantly greater in rats preexposed to brain stimulation. These findings suggest at least partial overlap of underlying substrates. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
134.
Stolzenberg Danielle S.; McKenna Jonathan B.; Keough Samantha; Hancock Rebecca; Numan Marilyn J.; Numan Michael 《Canadian Metallurgical Quarterly》2007,121(5):907
There is good evidence that interference with the mesolimbic dopamine (DA) system results in impaired maternal responding in postpartum female rats. However, whether activation of the mesolimbic DA system is capable of promoting maternal behavior has not been investigated. This study examined whether increasing DA activity in various brain regions of pregnancy-terminated, naive female rats would stimulate the onset of maternal behavior. Experiments 1 and 2 examined the effects of microinjection of various doses (0, 0.2, or 0.5 μg/0.5 μl/side) of a D? DA receptor agonist, SKF 38393, or a D? DA receptor agonist, quinpirole, into the nucleus accumbens (NA) on latency to show full maternal behavior, and Experiment 3 determined the effects of SKF 38393 injection into a control site. Finally, because the medial preoptic area (MPOA) is also important for maternal behavior, receives DA input, and expresses DA receptors, the authors examined whether microinjection of SKF 38393 into MPOA was capable of stimulating the onset of maternal behavior. Results indicated that microinjection of SKF 38393 into either the NA or the MPOA facilitates maternal responding in pregnancy-terminated rats. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
135.
Rebecca Vogel Anindita Saha Kish Chakrabarti Aldo Badano 《Journal of the Society for Information Display》2007,15(6):357-365
Abstract— As digital display systems replace film traditionally used for reading radiographic images, resource‐intensive acceptance testing must be performed to ensure that quality meets and maintains desired specifications. If machine observers can replace human readers, whose performances are highly variable, the results will be more consistent and less costly. To be effective, however, the automated observers must track human performance. An approach for a model observer, validated with human readers, for the evaluation of the visibility of low‐contrast small targets in high‐resolution and mobile displays under different ambient illumination, will be described. The displays were tested using CDMAM‐like digital phantoms containing disks of varying diameters and contrasts on a flat background. For this task, we find the best indicator of display performance to be the display's ability to represent small luminance contrast, not resolution or pixel size. The results confirm that high‐resolution systems perform better under low illumination while illuminance has a minor impact on the mobile‐display performance. Finally, the results show that the machine observer tracks the performance of human readers. Machine observers with proper validation can replace humans in the acceptance testing procedures, saving the testers both time and money. 相似文献
136.
137.
138.
Lorch Elizabeth Pugzles; Diener Mary Beth; Sanchez Rebecca Polley; Milich Richard; Welsh Richard; van den Broek Paul 《Canadian Metallurgical Quarterly》1999,91(2):273
This study explored influences of story structure properties on recall of story events by children with and without attention deficit hyperactivity disorder (ADHD). Participants listened to and retold 2 stories. Two properties of the stories' causal structure were derived: the number of causal connections an event has to other events and whether an event is on the causal chain linking events from beginning to end. The extent to which causal properties and the more subjective property of perceived importance predicted recall in the 2 groups of children was examined. Each property predicted recall, but there were group differences in sensitivity to causal structure that were moderated by intelligence level and gender. Variations in amount and allocation of cognitive resources applied to comprehension contributed to performance of children with ADHD. There are implications for understanding academic and social difficulties common in children with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
139.
Workflow Systems: Occasions for Success and Failure 总被引:3,自引:0,他引:3
Rebecca E. Grinter 《Computer Supported Cooperative Work (CSCW)》2000,9(2):189-214
Workflow technologies have created considerable discussion within the computer supported cooperative work community. Although a number of theoretical and empirical warnings about the difficulties of workflow systems have appeared, the technologies continue to be built and sold. This paper examines the use of one workflow-like system and outlines three cases when the technology supported the work of its users. Comparing these successful occasions with some reports of difficulties, this paper draws conclusions about the circumstances that led to tool usage. 相似文献
140.