全文获取类型
收费全文 | 6673篇 |
免费 | 1044篇 |
国内免费 | 723篇 |
专业分类
电工技术 | 271篇 |
综合类 | 673篇 |
化学工业 | 168篇 |
金属工艺 | 129篇 |
机械仪表 | 431篇 |
建筑科学 | 383篇 |
矿业工程 | 93篇 |
能源动力 | 32篇 |
轻工业 | 188篇 |
水利工程 | 45篇 |
石油天然气 | 59篇 |
武器工业 | 67篇 |
无线电 | 851篇 |
一般工业技术 | 784篇 |
冶金工业 | 1119篇 |
原子能技术 | 18篇 |
自动化技术 | 3129篇 |
出版年
2024年 | 73篇 |
2023年 | 195篇 |
2022年 | 270篇 |
2021年 | 312篇 |
2020年 | 316篇 |
2019年 | 272篇 |
2018年 | 255篇 |
2017年 | 227篇 |
2016年 | 304篇 |
2015年 | 268篇 |
2014年 | 375篇 |
2013年 | 404篇 |
2012年 | 453篇 |
2011年 | 504篇 |
2010年 | 462篇 |
2009年 | 454篇 |
2008年 | 441篇 |
2007年 | 450篇 |
2006年 | 396篇 |
2005年 | 356篇 |
2004年 | 318篇 |
2003年 | 245篇 |
2002年 | 228篇 |
2001年 | 196篇 |
2000年 | 128篇 |
1999年 | 90篇 |
1998年 | 57篇 |
1997年 | 43篇 |
1996年 | 53篇 |
1995年 | 27篇 |
1994年 | 27篇 |
1993年 | 17篇 |
1992年 | 15篇 |
1991年 | 13篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 8篇 |
1985年 | 14篇 |
1984年 | 13篇 |
1975年 | 6篇 |
1966年 | 8篇 |
1965年 | 8篇 |
1964年 | 15篇 |
1963年 | 7篇 |
1962年 | 6篇 |
1961年 | 6篇 |
1958年 | 10篇 |
1956年 | 9篇 |
1955年 | 15篇 |
1954年 | 7篇 |
排序方式: 共有8440条查询结果,搜索用时 9 毫秒
21.
Participants' usage of informational variables in learning visual relative-mass discrimination in collisions was tracked by means of PROBIT correlations. Four groups received feedback that was true or accorded with either of three nonspecificational cue variables. A majority in each group adopted the feedback, but several participants defied the false feedback. Unlike in previous research, the fit to data of the relative-mass invariant could not be bettered by post hoc linear combinations of the cues. Discriminability was lower in the use of the invariant. Analytic complexity was rejected as an explanation for discriminability differences. A "smart mechanism" for pickup of the relative-mass invariant was developed as an extension of G. Johansson's (1950/1994) vector model. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
22.
数据处理是编程的主要内容,字符数据作为一种重要的数据形式,在程序中应用非常广泛,而程序处理则比较复杂。本文以字符数据为例,着重分析与研究VC程序中字符串数据处理的几个主要方面,包括字符串的表示、处理和传递。 相似文献
23.
Multiple forms of a symbol-digit substitution task were used to provide a componential analysis of age differences in coding task performance. The results demonstrated age differences in feature encoding, memory, and visual search. A 2nd experiment was conducted with young adults to investigate a sensory deficit as a locus of age differences. The spatial contrast sensitivity deficit of older adults was simulated on forms by applying a digital filter. Persons in the age-simulated contrast condition performed worse than those in the normal contrast condition. The stimulus degradation effect was linked to visual search speed. The study illustrates the utility of componential analysis and offers direct support for the hypothesis that sensory deficits affect performance on tasks used to assess intelligence (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
24.
Gellatly Angus; Pilling Michael; Cole Geoff; Skarratt Paul 《Canadian Metallurgical Quarterly》2006,32(6):1422
Object substitution masking (OSM) is said to occur when a perceptual object is hypothesized that is mismatched by subsequent sensory evidence, leading to a new hypothesized object being substituted for the first. For example, when a brief target is accompanied by a longer lasting display of nonoverlapping mask elements, reporting of target features may be impaired. J. T. Enns and V. Di Lollo (2000) considered it an outstanding question whether OSM masks some or all aspects of a target. The authors report three experiments demonstrating that OSM can selectively affect target features. Participants may be able to detect a target while being unable to report other aspects of it or to report the color but not the orientation of a target (or vice versa). We discuss these findings in relation to two other visual phenomena. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
25.
Stimulus control of ring swimming was studied with male Siamese fighting fish (Betta splendens) using 2-component multiple schedules in which the components were correlated with the presence or absence of air bubbles in the water. In Experiment 1, either response-independent mirror presentations or extinction was juxtaposed with immediate response-dependent mirror presentations. Rates of ring swimming generally were higher with immediate reinforcement than with either response-independent mirror presentations or extinction. In Experiment 2, different durations of response-dependent mirror presentations were juxtaposed. Generally, higher rates of ring swimming occurred with 15-s than with 0-, 1-, or 3-s durations. Results demonstrate that stimulus control of responding can be established with these fish under several conditions of differential reinforcement. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
26.
Phoneme identification with audiovisually discrepant stimuli is influenced hy information in the visual signal (the McGurk effect). Additionally, lexical status affects identification of auditorily presented phonemes. The present study tested for lexical influences on the McGurk effect. Participants identified phonemes in audiovisually discrepant stimuli in which lexical status of the auditory component and of a visually influenced percept was independently varied. Visually influenced (McGurk) responses were more frequent when they formed a word and when the auditory signal was a nonword (Experiment 1). Lexical effects were larger for slow than for fast responses (Experiment 2), as with auditory speech, and were replicated with stimuli matched on physical properties (Experiment 3). These results are consistent with models in which lexical processing of speech is modality independent. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
27.
Two experiments examined the disruption of feature-based selection in triple-conjunction search at multiple target transfers. In Experiment 1, after 10 training sessions, a new target possessing previous distractor features was introduced. This produced disruption in RT and fixation number, but no disruption in feature-based selection. Specifically, there was a tendency to fixate objects sharing the target's contrast polarity and shape and this did not change even upon transfer to the new target. In Experiment 2, 30 training sessions were provided with three target transfers. At the first transfer, the results replicated Experiment 1. Subsequent transfers did not produce disruption on any measure. These findings are discussed in terms of strength theory, Guided Search, rule-based approaches to perceptual learning, and the area activation model. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
In a change detection paradigm, a target object in a natural scene either rotated in depth, was replaced by another object token, or remained the same. Change detection performance was reliably higher when a target postcue allowed participants to restrict retrieval and comparison processes to the target object (Experiment 1). Change detection performance remained excellent when the target object was not attended at change (Experiment 2) and when a concurrent verbal working memory load minimized the possibility of verbal encoding. (Experiment 3). Together, these data demonstrate that visual representations accumulate in memory from attended objects as the eyes and attention are oriented within a scene and that change blindness derives, at least in part, from retrieval and comparison failure. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
29.
In Part 1 of this two-part series, we introduced Katamic memory—a neural network architecture capable of robust sequence learning and recognition. In Part 2, we introduce the Blobs World taskjdomain for language learning and describe the DETE language learning system, which is composed of over 50 Katamic memory modules. DETE currently learns small subsets of English and Spanish via association with perceptual! motor inputs. In addition to Kaiamic memory, DETE employs several other novel features: (1) use of feature planes, to encode visual shapes, spatial relationships and the motions of objects, (2) phase-locking of neural firing, in order to represent focus of atention and to bind objects across multiple feature planes, and (3) a method for encoding temporal relationships, so that DETE can learn utterances involving the immediate past and future. We compare DETE to related models and discuss the implications of this approach for language-learning research. 相似文献
30.
动态过程监视的最佳显示方式研究 总被引:1,自引:0,他引:1
文中讨论了人机界面的视学工效问题,通过实验评价了用于动态过程监视与控制的三种CRT显示方式的工效,并由此得出人类视学系统反应对图形方式更优于对数字方式,图形与数字的复合方式。 相似文献