全文获取类型
收费全文 | 4864篇 |
免费 | 679篇 |
国内免费 | 604篇 |
专业分类
电工技术 | 156篇 |
综合类 | 463篇 |
化学工业 | 75篇 |
金属工艺 | 44篇 |
机械仪表 | 322篇 |
建筑科学 | 213篇 |
矿业工程 | 30篇 |
能源动力 | 21篇 |
轻工业 | 54篇 |
水利工程 | 37篇 |
石油天然气 | 24篇 |
武器工业 | 76篇 |
无线电 | 436篇 |
一般工业技术 | 343篇 |
冶金工业 | 871篇 |
原子能技术 | 17篇 |
自动化技术 | 2965篇 |
出版年
2024年 | 48篇 |
2023年 | 134篇 |
2022年 | 215篇 |
2021年 | 194篇 |
2020年 | 199篇 |
2019年 | 131篇 |
2018年 | 129篇 |
2017年 | 150篇 |
2016年 | 170篇 |
2015年 | 181篇 |
2014年 | 326篇 |
2013年 | 344篇 |
2012年 | 383篇 |
2011年 | 386篇 |
2010年 | 329篇 |
2009年 | 332篇 |
2008年 | 336篇 |
2007年 | 363篇 |
2006年 | 283篇 |
2005年 | 264篇 |
2004年 | 253篇 |
2003年 | 205篇 |
2002年 | 160篇 |
2001年 | 124篇 |
2000年 | 71篇 |
1999年 | 60篇 |
1998年 | 57篇 |
1997年 | 41篇 |
1996年 | 36篇 |
1995年 | 26篇 |
1994年 | 11篇 |
1993年 | 11篇 |
1992年 | 13篇 |
1991年 | 9篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1966年 | 10篇 |
1965年 | 8篇 |
1964年 | 17篇 |
1963年 | 17篇 |
1962年 | 8篇 |
1961年 | 8篇 |
1960年 | 5篇 |
1959年 | 12篇 |
1958年 | 5篇 |
1957年 | 5篇 |
1956年 | 12篇 |
1955年 | 5篇 |
排序方式: 共有6147条查询结果,搜索用时 15 毫秒
21.
22.
23.
The main purpose of the study reported here was to investigate the relative importance of complexity of syllable structure and task differences in measuring phonological awareness in low-literacy adults. This study is a replication of a study with children conducted by S. A. Stahl and B. A. Murray (1994). Results indicated that the complexity of syllable structure did indeed better describe the construct of phonological awareness in low-literacy adults. At the same time, the authors also found some differences in the pattern of literacy acquisition for their Spanish adults in comparison with child literacy acquisition in English. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
24.
Through two experiments, the study sought to emphasize the usefulness of the visual and kinesthetic imagery in mental practice. In Experiment 1, it was hypothesized that when the task to be learned through mental practice necessitates the reproduction of a form by drawing, the visual image, which provides a wide span of apprehension, is more suitable than the kinesthetic image. On the other hand, the kinesthetic image that supplies inputs from the muscles' positions and movements should be more appropriate for the acquisition of the duration of the drawing. In Experiment 2, it was hypothesized that the task, transformed into a motor task necessitating minute coordination of the two hands, would benefit more from kinesthetic imagery. To have optimal control over what was actually experienced during mental practice, the participants' imagery skills were measured. The participants also benefited from prior imagery training. The results demonstrate that when using mental practice to initially acquire a task, visual imagery is better for tasks that emphasize form while kinesthetic imagery is better for those tasks that emphasize timing or minute coordination of the two hands. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
25.
26.
Trust for Ubiquitous,Transparent Collaboration 总被引:1,自引:0,他引:1
In this paper, trust-based recommendations control the exchange of personal information between handheld computers. Combined with explicit risk analysis, this enables unobtrusive information exchange, while limiting access to confidential information. The same model can be applied to a wide range of mobile computing tasks, such as managing personal address books and electronic diaries, to automatically provide an appropriate level of security. Recommendations add structure to the information, by associating categories with data and with each other, with degrees of trust belief and disbelief. Since categories also in turn confer privileges and restrict actions, they are analogous to rôles in a Rôle-Based Access Control system, while principals represent their trust policies in recommendations. Participants first compute their trust in information, by combining their own trust assumptions with others' policies. Recommendations are thus linked together to compute a considered, local trust assessment. Actions are then moderated by a risk assessment, which weighs up costs and benefits, including the cost of the user's time, before deciding whether to allow or forbid the information exchange, or ask for help. By unifying trust assessments and access control, participants can take calculated risks to automatically yet safely share their personal information. 相似文献
27.
Performance on antisaccade trials requires the inhibition of a prepotent response (i.e., don't look at the flashing cue) and the generation and execution of a correct saccade in the opposite direction. The authors attempted to further specify the role of working memory (WM) span differences in the antisaccade task. They tested high- and low-span individuals on variants of prosaccade and antisaccade trials in which an eye movement is the sole requirement. In 3 experiments, they demonstrated the importance of WM span differences in both suppression of a reflexive saccade and generation of a volitional eye movement. The results support the contention that individual differences in WM span are not exclusively due to differences in inhibition but also reflect differences in directing the focus of attention. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
Before 12 months of age, infants have difficulties coordinating and sequencing their movements to retrieve an object concealed in a box. This study examined (a) whether young infants can discover effective retrieval solutions and consolidate movement coordination earlier if exposed regularly to such a task and (b) whether different environments, indexed by box transparency, would impact the rate of learning and time of discovery of these solutions. Infants (N=12) were presented with an object retrieval task every week from 6 1/2 months of age until they were able to retrieve the toy from the box using coordinated two-handed patterns for 3 weeks. To reach that criterion, infants tested with an opaque box took 2 1/2 months and infants tested with a semitransparent box took 1 1/2 months. Both groups outperformed age-matched controls who received a one-time exposure to the task. Repeated exposure to the task and vision of the toy significantly enhanced this process of solution discovery. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
29.
Verbrugge Sara; Dieussaert Kristien; Schaeken Walter; Van Belle William 《Canadian Metallurgical Quarterly》2004,58(2):106
Evidence from reasoning tasks shows that promises and threats both tend to receive biconditional interpretations. They also both display high speaker control. On the face of it, the only difference seems to be the positive or negative signing of the consequent. In a promise, the speaker tries to persuade the hearer to do something by holding out the prospect of a particular reward; in a threat, the speaker tries to refrain the hearer from doing something by holding out the prospect of a particular punishment. This paper investigates the respects in which conditional promises and threats differ further by means of an inference task. The credibility of the consequent was manipulated in order to examine whether the acceptability ratings of inferences based on promises and on threats would be equally affected. The results of the inference task and an analysis of the reasons people give for their answers suggest that the credibility of promises is less affected by the use of excessive consequents than the credibility of threats. In other words, promise remains debt, whereas threat is another matter. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
30.
介绍了一种用可编程控制器(PLC)实现捆扎机自动控制的设计方案,详细地介绍了设计过程,给出了完整的程序流程图和部分控制程序。 相似文献