全文获取类型
收费全文 | 4108篇 |
免费 | 108篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 25篇 |
综合类 | 3篇 |
化学工业 | 617篇 |
金属工艺 | 18篇 |
机械仪表 | 32篇 |
建筑科学 | 202篇 |
矿业工程 | 85篇 |
能源动力 | 55篇 |
轻工业 | 433篇 |
水利工程 | 26篇 |
石油天然气 | 6篇 |
无线电 | 117篇 |
一般工业技术 | 428篇 |
冶金工业 | 1708篇 |
原子能技术 | 9篇 |
自动化技术 | 453篇 |
出版年
2022年 | 34篇 |
2021年 | 64篇 |
2020年 | 34篇 |
2019年 | 48篇 |
2018年 | 50篇 |
2017年 | 60篇 |
2016年 | 74篇 |
2015年 | 53篇 |
2014年 | 58篇 |
2013年 | 217篇 |
2012年 | 144篇 |
2011年 | 186篇 |
2010年 | 169篇 |
2009年 | 153篇 |
2008年 | 199篇 |
2007年 | 198篇 |
2006年 | 143篇 |
2005年 | 168篇 |
2004年 | 136篇 |
2003年 | 155篇 |
2002年 | 126篇 |
2001年 | 97篇 |
2000年 | 84篇 |
1999年 | 99篇 |
1998年 | 82篇 |
1997年 | 87篇 |
1996年 | 99篇 |
1995年 | 75篇 |
1994年 | 85篇 |
1993年 | 100篇 |
1992年 | 96篇 |
1991年 | 37篇 |
1990年 | 84篇 |
1989年 | 68篇 |
1988年 | 70篇 |
1987年 | 71篇 |
1986年 | 72篇 |
1985年 | 61篇 |
1984年 | 53篇 |
1983年 | 48篇 |
1982年 | 42篇 |
1981年 | 32篇 |
1980年 | 21篇 |
1979年 | 33篇 |
1978年 | 29篇 |
1977年 | 14篇 |
1976年 | 19篇 |
1975年 | 17篇 |
1974年 | 13篇 |
1973年 | 16篇 |
排序方式: 共有4217条查询结果,搜索用时 0 毫秒
31.
32.
L. B. Silverstein (see record 1994-17264-001) makes excellent use of recent data on nonhuman primate behavior to argue for the complexity of interaction between biological and environmental variables in the ontogeny of male parental behavior. She has read the current discourse in primate evolutionary studies with a careful and sophisticated eye for the evidence emerging from primate field studies over the last decade of great plasticity in primate behavior. Yet, as a biosocial anthropologist, fundamental questions remain for S. Sperling about how useful such data about parenting behavior in monkeys and apes are to discussions of the complex cultural, historical, and socioeconomic variables that underlie variations in human male parenting. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
33.
34.
Robert L. Stevenson Susan M. Schweizer 《Journal of Mathematical Imaging and Vision》1992,2(2-3):137-154
This paper introduces a new nonlinear filtering structure for filtering image data that have been corrupted by both impulsive and nonimpulsive additive noise. Like other nonlinear filters, the proposed filtering structure uses order-statistic operations to remove the effects of the impulsive noise. Unlike other filters, however, nonimpulsive noise is smoothed by using a maximum a posteriori estimation criterion. The prior model for the image is a novel Markov random-field model that models image edges so that they are accurately estimated while additive Gaussian noise is smoothed. The Markov random-field-based prior is chosen such that the filter has desirable analytical and computational properties. The estimate of the signal value is obtained at the unique minimum of the a posteriori log likelihood function. This function is convex so that the output of the filter can be easily computed by using either digital or analog computational methods. The effects of the various parameters of the model will be discussed, and the choice of the predetection order statistic filter will also be examined. Example outputs under various noise conditions will be given. 相似文献
35.
Paul de Lamene是18世纪早期英国银器鼎盛时期一颗耀眼的明星,他也是那个时代英国最多产的银匠。 相似文献
36.
A commercially available and widely used servo-controlled ventilator has been modified to provide controlled inspiratory resistive unloading of the human respiratory system. This is achieved by establishing a positive mouth pressure throughout inspiration in a constant proportion to instantaneous flow, i.e., the ratio of mouth pressure to flow, which defines the "assistance," remaining constant. The performance of this device has been evaluated in four healthy subjects during steady-state, constant-load cycling (20-120 W). It is demonstrated that i) the device can successfully implement controlled degrees of inspiratory assistance on a breath-to-breath basis; ii) the assistance can be sustained over a substantial range of ventilatory drive (i.e., for ventilations up to some 30 1/min) and to an extent which approaches a 100 percent reduction of the normal respiratory resistance. This device should prove useful in experimental and clinical investigations of the respiratory responses to resistive unloading of the respiratory system. 相似文献
37.
Klatzky Roberta L.; Lederman Susan J.; Reed Catherine 《Canadian Metallurgical Quarterly》1987,116(4):356
The availability and salience of object attributes under haptic exploration, with and without vision, were assessed by 2 tasks in which Ss sorted objects that varied factorially in size, shape, texture, and hardness. In the directed-discrimination task, Ss were instructed to sort along a particular dimension. Although levels on all dimensions were easily discriminated, shape was relatively less so for haptic explorers without vision, as was hardness for those using vision and haptics. Size was least discriminable for both groups. In the free-sorting task, Ss were to sort objects by similarity. Three groups used haptic exploration only; these were differentiated by the experimenters' definition of object similarity: unbiased haptics, haptically biased haptics, haptics plus visual imagery. A 4th group used vision as well as haptics, with instructions like those of the unbiased haptics group. Results support the contention that the haptic and visual systems have distinct encoding pathways, with haptics oriented toward the encoding of substance rather the shape. This may reflect a direct influence of haptic exploratory procedures. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
38.
Susan Owens 《Energy Policy》1985,13(6):546-558
During the latter half of the 19ar 1970s there was great concern about potential conflicts over energy development proposals in the UK, most of which were expected to emerge within the framework of land use planning procedures and the associated opportunities for public participation. While there has been widespread dissatisfaction with the way in which the planning system handles energy developments, there is little consensus about the nature of the problem or about possible solutions to it. Greatly reduced energy forecasts allow a pause for reflection, but it is argued that there is no room for complacency about conflict over energy developments in future. 相似文献
39.
Toward a comprehensive assessment of fundamental motivation: Factor structure of the Reiss Profiles.
Two instruments were developed to provide a comprehensive assessment of the strength of a person's fundamental end goals and motivational sensitivities. One instrument was a self-report inventory for adolescents and adults in general, and the other was an informant-rating scale for adolescents and adults with mental retardation and development disabilities. Exploratory and confirmatory factor analyses and test-retest reliabilities are reported in 7 studies, with independent samples of participants from diverse geographical areas, occupations, and social groups, N?=?2,548. Each instrument was found to have a 15-factor solution, and the 2 solutions were similar to one another. Because the factors assess universal motives that are also seen in animals, a genetics-behavior-cognitive model of fundamental motivation is suggested. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
40.
Evan M. de Joya Brett M. Colbert Pei-Ciao Tang Byron L. Lam Jun Yang Susan H. Blanton Derek M. Dykxhoorn Xuezhong Liu 《International journal of molecular sciences》2021,22(8)
Hearing loss is the most common sensory disorder with ~466 million people worldwide affected, representing about 5% of the population. A substantial portion of hearing loss is genetic. Hearing loss can either be non-syndromic, if hearing loss is the only clinical manifestation, or syndromic, if the hearing loss is accompanied by a collage of other clinical manifestations. Usher syndrome is a syndromic form of genetic hearing loss that is accompanied by impaired vision associated with retinitis pigmentosa and, in many cases, vestibular dysfunction. It is the most common cause of deaf-blindness. Currently cochlear implantation or hearing aids are the only treatments for Usher-related hearing loss. However, gene therapy has shown promise in treating Usher-related retinitis pigmentosa. Here we review how the etiologies of Usher-related hearing loss make it a good candidate for gene therapy and discuss how various forms of gene therapy could be applied to Usher-related hearing loss. 相似文献