全文获取类型
收费全文 | 14064篇 |
免费 | 1748篇 |
国内免费 | 924篇 |
专业分类
电工技术 | 622篇 |
技术理论 | 1篇 |
综合类 | 1341篇 |
化学工业 | 529篇 |
金属工艺 | 567篇 |
机械仪表 | 1200篇 |
建筑科学 | 1095篇 |
矿业工程 | 3942篇 |
能源动力 | 467篇 |
轻工业 | 263篇 |
水利工程 | 688篇 |
石油天然气 | 354篇 |
武器工业 | 62篇 |
无线电 | 879篇 |
一般工业技术 | 610篇 |
冶金工业 | 1174篇 |
原子能技术 | 29篇 |
自动化技术 | 2913篇 |
出版年
2024年 | 32篇 |
2023年 | 138篇 |
2022年 | 374篇 |
2021年 | 528篇 |
2020年 | 621篇 |
2019年 | 309篇 |
2018年 | 276篇 |
2017年 | 312篇 |
2016年 | 393篇 |
2015年 | 529篇 |
2014年 | 947篇 |
2013年 | 771篇 |
2012年 | 1365篇 |
2011年 | 1300篇 |
2010年 | 989篇 |
2009年 | 995篇 |
2008年 | 973篇 |
2007年 | 1016篇 |
2006年 | 881篇 |
2005年 | 736篇 |
2004年 | 626篇 |
2003年 | 540篇 |
2002年 | 452篇 |
2001年 | 379篇 |
2000年 | 291篇 |
1999年 | 225篇 |
1998年 | 151篇 |
1997年 | 127篇 |
1996年 | 105篇 |
1995年 | 85篇 |
1994年 | 67篇 |
1993年 | 47篇 |
1992年 | 28篇 |
1991年 | 27篇 |
1990年 | 18篇 |
1989年 | 21篇 |
1988年 | 10篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1977年 | 2篇 |
1966年 | 2篇 |
1959年 | 2篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1955年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
Sagaspe Patricia; Charles André; Taillard Jacques; Bioulac Bernard; Philip Pierre 《Canadian Metallurgical Quarterly》2003,57(4):265
The literature contains inconsistent data on the effects of acute sleep deprivation on the superior cognitive functions. The primary purpose of this study is to determine the effectiveness of inhibition, one of the functions of the working memory executive centre (EC), over an extended, 36-hour waking period. Inhibition is a cognitive mechanism whereby individuals ignore non-relevant information recorded in their working memory. We also tested the effects of a 36- hour period of acute sleep deprivation on simple reaction time. Twelve young, healthy volunteers (M=21.5 years, ?=2.3) performed a random generation task involving letters and a simple reaction time psychomotor test over four sessions held at 10-hour intervals. Each participant was assigned a "constant routine." Participants were kept awake in a prone position within a room whose environment was held strictly constant (light, noise, temperature, meals, etc.). This control procedure provided assurance that any variation in participant performance was solely caused by sleep deprivation. The random generation task, nearly two minutes in length, consisted in verbally producing a sequence of 100 letters in a random fashion (i.e. by inhibiting, for example, alphabetical order) and by keeping to a set rhythm... (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
63.
简要介绍了硅粉的理化性能,分析了WG硅微粉的形成过程,并进行了用于塑料制品的使用性能的试验研究,为硅粉用于塑料制品工艺提供了有利的借鉴。 相似文献
64.
The relationship between facial expression and gaze processing was investigated with the Garner selective attention paradigm. In Experiment 1, participants performed expression judgments without interference from gaze, but expression interfered with gaze judgments. Experiment 2 replicated these results across different emotions. In both experiments, expression judgments occurred faster than gaze judgments, suggesting that expression was processed before gaze could interfere. In Experiments 3 and 4, the difficulty of the emotion discrimination was increased in two different ways. In both cases, gaze interfered with emotion judgments and vice versa. Furthermore, increasing the difficulty of the emotion discrimination resulted in gaze and expression interactions. Results indicate that expression and gaze interactions are modulated by discriminability. Whereas expression generally interferes with gaze judgments, gaze direction modulates expression processing only when facial emotion is difficult to discriminate. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
65.
In long-term memory, negative information is better remembered than neutral information. Differences in processes important to working memory may contribute to this emotional memory enhancement. To examine the effect that the emotional content of stimuli has on working memory performance, the authors asked participants to perform working memory tasks with negative and neutral stimuli. Task accuracy was unaffected by the emotional content of the stimuli. Reaction times also did not differ for negative relative to neutral words, but on an n-back task using faces, participants were slower to respond to fearful faces than to neutral faces. These results suggest that although emotional content does not have a robust effect on working memory, in some instances emotional salience can impede working memory performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
66.
从结构组成及工作原理、技术特点及优势等方面简述了SSFC伸缩装置,并对其安装工艺及关键质量控制点和维修及保养进行了阐述,以推广SSFC伸缩装置的应用。 相似文献
67.
We propose subspace distance measures to analyze the similarity between intrapersonal face subspaces, which characterize the variations between face images of the same individual. We call the conventional intrapersonal subspace average intrapersonal subspace (AIS) because the image differences often come from a large number of persons. An intrapersonal subspace is referred to as specific intrapersonal subspace (SIS) if the image differences are from just one person. We demonstrate that SIS varies significantly from person to person, and most SISs are not similar to AIS. Based on these observations, we introduce the maximum a posteriori (MAP) adaptation to the problem of SIS estimation, and apply it to the Bayesian face recognition algorithm. Experimental results show that the adaptive Bayesian algorithm outperforms the non-adaptive Bayesian algorithm as well as Eigenface and Fisherface methods if a small number of adaptation images are available. 相似文献
68.
铝电解电容器用橡皮塞中铁的测定 总被引:1,自引:0,他引:1
主要研究了用硫氰酸钾作显色剂,用分光光度法测定橡皮塞中铁含量的方法。并对国产和进口橡皮塞做了比较,为铝电解电容器质量水平的提高提供一条新思路。 相似文献
69.
70.