全文获取类型
收费全文 | 15431篇 |
免费 | 683篇 |
国内免费 | 7篇 |
专业分类
16121篇 |
出版年
2020年 | 169篇 |
2019年 | 172篇 |
2018年 | 265篇 |
2017年 | 235篇 |
2016年 | 272篇 |
2015年 | 208篇 |
2014年 | 261篇 |
2013年 | 1096篇 |
2012年 | 477篇 |
2011年 | 436篇 |
2010年 | 303篇 |
2009年 | 277篇 |
2008年 | 401篇 |
2007年 | 421篇 |
2006年 | 365篇 |
2005年 | 360篇 |
2004年 | 311篇 |
2003年 | 273篇 |
2002年 | 301篇 |
2001年 | 673篇 |
2000年 | 667篇 |
1999年 | 453篇 |
1998年 | 169篇 |
1997年 | 163篇 |
1996年 | 163篇 |
1995年 | 136篇 |
1992年 | 361篇 |
1991年 | 340篇 |
1990年 | 356篇 |
1989年 | 301篇 |
1988年 | 287篇 |
1987年 | 283篇 |
1986年 | 256篇 |
1985年 | 257篇 |
1984年 | 238篇 |
1983年 | 203篇 |
1982年 | 157篇 |
1979年 | 220篇 |
1978年 | 172篇 |
1977年 | 148篇 |
1975年 | 190篇 |
1974年 | 230篇 |
1973年 | 229篇 |
1972年 | 183篇 |
1971年 | 180篇 |
1970年 | 148篇 |
1969年 | 176篇 |
1968年 | 210篇 |
1967年 | 191篇 |
1966年 | 156篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
191.
R Goertchen N Grunow T Münchow E Goertchen 《Psychiatrie, Neurologie, und medizinische Psychologie》1986,38(3):128-132
Based on 2130 autopsies with a hypertension it is reported on the hypertensive CNS-lesions. The frequency of encephalomalacia was 12%. By 9.7% was founded brain haemorrhages. The relapse rate of haemorrhages was about 5%. The encephalomalacia existed by way of secondary finding in 24.7%, and the haemorrhage in 2.2%. The investigations showed an important arteriosclerosis by 39.8% in haemorrhages and by 51.6% in brain infarct. It was remarkable by the hypertensive brain haemorrhages a dominant right hemisphere. 相似文献
192.
193.
194.
Varieties of perceptual independence 总被引:6,自引:0,他引:6
195.
196.
197.
198.
Retrospective coding in pigeons' delayed matching-to-sample 总被引:2,自引:0,他引:2
P J Urcuioli T R Zentall 《Journal of experimental psychology. Animal behavior processes》1986,12(1):69-77
In this study we examined how coding processes in pigeons' delayed matching-to-sample were affected by the stimuli to be remembered. In Experiment 1, two groups of pigeons initially learned 0-delay matching-to-sample with identical comparison stimuli (vertical and horizontal lines) but with different sample stimuli (red and green hues or vertical and horizontal lines). Longer delays were then introduced between sample offset and comparison onset to assess whether pigeons were prospectively coding the same events (viz., the correct line comparisons) or retrospectively coding different events (viz., their respective sample stimuli). The hue-sample group matched more accurately and showed a slower rate of forgetting than the line-sample group. In Experiment 2, pigeons were trained with either hues or lines as both sample and comparison stimuli, or with hue samples and line comparisons or vice versa. Subsequent delay tests revealed that the hue-sample groups remembered more accurately and generally showed slower rates of forgetting than the line-sample groups. Comparison dimension had little or no effect on performance. Together, these data suggest that pigeons retrospectively code the samples in delayed matching-to-sample. 相似文献
199.
T R Zentall P Jackson-Smith J A Jagielo G B Nallan 《Journal of experimental psychology. Animal behavior processes》1986,12(2):153-159
Categorical coding is the tendency to respond similarly to discriminated stimuli. Past research indicates that pigeons can categorize colors according to at least three spectral regions. Two present experiments assessed the categorical coding of shapes and the existence of a higher order color category (all colors). Pigeons were trained on two independent tasks (matching-to-sample, and oddity-from-sample). One task involved red and a plus sign, the other a circle and green. On test trials one of the two comparison stimuli from one task was replaced by one of the stimuli from the other task. Differential performance based on which of the two stimuli from the other task was introduced suggested categorical coding rules. In Experiment 1 evidence for the categorical coding of sample shapes was found. Categorical color coding was also found; however, it was the comparison stimuli rather than the samples that were categorically coded. Experiment 2 replicated the categorical shape sample effect and ruled out the possibility that the particular colors used were responsible for the categorical coding of comparison stimuli. Overall, the results indicate that pigeons can develop categorical rules involving shapes and colors and that the color categories can be hierarchical. 相似文献
200.