全文获取类型
收费全文 | 33115篇 |
免费 | 1345篇 |
国内免费 | 8篇 |
出版年
2019年 | 436篇 |
2018年 | 568篇 |
2017年 | 594篇 |
2016年 | 590篇 |
2015年 | 428篇 |
2014年 | 541篇 |
2013年 | 2417篇 |
2012年 | 995篇 |
2011年 | 1056篇 |
2010年 | 621篇 |
2009年 | 617篇 |
2008年 | 913篇 |
2007年 | 901篇 |
2006年 | 845篇 |
2005年 | 753篇 |
2004年 | 743篇 |
2003年 | 664篇 |
2002年 | 709篇 |
2001年 | 1025篇 |
2000年 | 937篇 |
1999年 | 715篇 |
1998年 | 386篇 |
1997年 | 321篇 |
1996年 | 313篇 |
1992年 | 559篇 |
1991年 | 547篇 |
1990年 | 529篇 |
1989年 | 541篇 |
1988年 | 534篇 |
1987年 | 496篇 |
1986年 | 525篇 |
1985年 | 578篇 |
1984年 | 456篇 |
1983年 | 438篇 |
1982年 | 359篇 |
1981年 | 345篇 |
1979年 | 528篇 |
1978年 | 383篇 |
1977年 | 313篇 |
1976年 | 361篇 |
1975年 | 434篇 |
1974年 | 487篇 |
1973年 | 509篇 |
1972年 | 408篇 |
1971年 | 383篇 |
1970年 | 378篇 |
1969年 | 408篇 |
1968年 | 488篇 |
1967年 | 421篇 |
1966年 | 422篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Suicides among older adults in the United States and Canada in the last decade have accounted for an increasing share of all suicides. In both countries the use of firearms among older adults has steadily increased. Despite these trends, little is known about the extent to which crisis centers are prepared to prevent elder suicide. A survey of AAS-listed crisis prevention centers examined the training, knowledge, and current practices relevant to elder suicide among personnel in 321 crisis prevention centers in both countries. Results revealed insufficient training, a lack of familiarity with recent suicide trends, and limited outreach to older adults. 相似文献
42.
The country‐of‐origin effect is a topic central to the field of international marketing. Country of origin has been found to exert a particularly potent effect on consumer evaluation in situations where there is a strong link between a country and a particular product category. The present study provides further insight into how this particular effect can be understood. Drawing on a novel conceptualization of how country image and product categories interact, this study tested the relative evaluative relevance of product category with respect to estimates of brand equity across a variety of product categories. The findings suggest that facets of a country's image that are more closely related to the evaluation situation exert a greater influence on the evaluation of brands. This result encourages scholars as well as practitioners to re‐evaluate which situations might cause the country of origin effect to hold managerial relevance and paves the way for new paths toward a more comprehensive understanding of the effect. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
43.
Communication is a multimodal phenomenon. The cognitive mechanisms supporting it are still understudied. We explored a natural dataset of academic lectures to determine how communication modalities are used and coordinated during the presentation of complex information. Using automated and semi‐automated techniques, we extracted and analyzed, from the videos of 30 speakers, measures capturing the dynamics of their body movement, their slide change rate, and various aspects of their speech (speech rate, articulation rate, fundamental frequency, and intensity). There were consistent but statistically subtle patterns in the use of speech rate, articulation rate, intensity, and body motion across the presentation. Principal component analysis also revealed patterns of system‐like covariation among modalities. These findings, although tentative, do suggest that the cognitive system is integrating body, slides, and speech in a coordinated manner during natural language use. Further research is needed to clarify the specific coordination patterns that occur between the different modalities. 相似文献
44.
45.
46.
47.
A series of stereograms are presented which demonstrate that texture boundaries can strongly influence the perception of discontinuities between neighbouring three-dimensional (3-D) surfaces portrayed by means of stereo cues. In these demonstration figures, no stereo information is available in the immediate vicinity of the boundary between the two 3-D stereo surfaces because all texture in that region is removed in one eye's view. On the other hand, various forms of texture boundary information are provided in the resulting monocular region. This stimulus paradigm is used to explore the question: what influence does texture boundary information have on the nature of the perceived 3-D surface that is interpolated between two stimulus regions which carry stereo cues? It is shown that if a clear-cut texture boundary is present in the monocular region then this is used by the human visual system to fix the perceived location of 3-D crease and step surface discontinuities between the stereo regions. Collett (1985) explored this issue with a similar methodology and reported weak and unreliable assistance from monocular texture boundaries in helping shape 3-D stereo surface discontinuities. The strong and robust phenomena demonstrated here seem to rely on two main differences between the present stimuli and those of Collett. In the present stimuli, figurally continuous textures containing strong texture boundaries are used, together with a technique for minimising the complications, including binocular rivalry, that arise from the borders of the stimulus regions present in only one half of each stereogram. 相似文献
48.
49.
50.