全文获取类型
收费全文 | 24426篇 |
免费 | 486篇 |
国内免费 | 3篇 |
专业分类
24915篇 |
出版年
2020年 | 274篇 |
2019年 | 327篇 |
2018年 | 424篇 |
2017年 | 430篇 |
2016年 | 488篇 |
2015年 | 370篇 |
2014年 | 473篇 |
2013年 | 2006篇 |
2012年 | 798篇 |
2011年 | 751篇 |
2010年 | 530篇 |
2009年 | 494篇 |
2008年 | 706篇 |
2007年 | 708篇 |
2006年 | 642篇 |
2005年 | 612篇 |
2004年 | 565篇 |
2003年 | 515篇 |
2002年 | 588篇 |
2001年 | 775篇 |
2000年 | 770篇 |
1999年 | 582篇 |
1998年 | 303篇 |
1997年 | 289篇 |
1996年 | 266篇 |
1995年 | 266篇 |
1994年 | 240篇 |
1992年 | 465篇 |
1991年 | 446篇 |
1990年 | 445篇 |
1989年 | 387篇 |
1988年 | 355篇 |
1987年 | 349篇 |
1986年 | 328篇 |
1985年 | 347篇 |
1984年 | 346篇 |
1983年 | 316篇 |
1982年 | 268篇 |
1981年 | 274篇 |
1980年 | 227篇 |
1979年 | 342篇 |
1978年 | 289篇 |
1977年 | 260篇 |
1976年 | 233篇 |
1975年 | 299篇 |
1974年 | 335篇 |
1973年 | 303篇 |
1972年 | 247篇 |
1969年 | 235篇 |
1968年 | 258篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
Ratings of pre-morbid intelligence level, derived from the hospital charts of 26 chronic schizophrenics, were correlated with the post-mortem brain volume measures of cortex, white matter, central grey matter, and ventricles. Contrary to hypothesis, no significant correlations were found. 相似文献
12.
T L Stawar 《Perceptual and motor skills》1988,67(3):960-962
The IES Arrow-Dot was administered to 41 cocaine detoxification patients. This group's scores indicated lower ego functioning and higher impulsivity and superego functioning than other clinical samples. No significant differences were noted between the Arrow-Dot scores of patients who successfully completed the program and those who did not. 相似文献
13.
Sprague-Dawley rats drank sweetened (3% dextrose + 0.144% saccharin, w/v) or unflavored water for 18 days and subsequent pain reactivity was assessed using a hot plate. Compared to the rats that consumed unflavored water, the rats that consumed sweet water responded more quickly on the hot plate indicating that their threshold for pain was lowered. Another group of rats given identical exposure to the fluids had their brains prepared for measuring opiate receptor binding using the delta-receptor ligand [3H]D-Ala-D-Leu-enkephalin ([3H]DADLE) and the mu-receptor selective ligand [3H]Tyr-D-Ala-Gly-MePhe-Gly-ol ([ 3H]DAGO). Binding of these opiates to mu- and delta-receptors in the cerebral cortex, striatum, hippocampus, hypothalamus, brain stem, and remaining brain regions was the same for the rats that drank sweet fluids and those that drank unflavored water. These findings suggest that drinking sweet fluids lowers pain thresholds but does not alter mu- and delta-receptors. 相似文献
14.
15.
High-resolution CRT displays are subject togeometric distortion: lines that are straight in the internal coordinates of the graphics software and hardware are curved when projected onto a plane in the observer’s line of sight. As the available resolution of CRT screens increases, it becomes more difficult to measure and correct for this distortion. We present a simple, highly accurate method for determining the mapping between internal coordinates and the viewing plane. It requires that an observer, using a calibration program, adjust triples of displayed points until they are collinear. A metal straightedge placed between the observer and the screen aids in this judgment. We describe the calibration of an IBM Enhanced Graphics Display in high-resolution mode (350 × 640 pixels), and illustrate how to use the estimated mapping to choose internal coordinates to draw undistorted figures that are accurate to within 0.5 pixel. The method can be used to assess or to correct the accuracy of visual displays. The method is relevant to experiments in spatial vision, spatial perception, perception of dot patterns, and any application in which geometrically accurate stimuli are required. 相似文献
16.
This article presents a simulation-based tutorial system for exploring parallel distributed processing (PDP) models of information processing. The system consists of software and an accompanying handbook. The intent of the package is to make the ideas underlying PDP accessible and to disseminate some of the main simulation programs that we have developed. This article presents excerpts from the handbook that describe the approach taken, the organization of the handbook, and the software that comes with it. An example is given that illustrates the approach we have taken to teaching PDP, which involves presentation of relevant mathematical background, together with tutorial exercises that make use of the simulation programs. 相似文献
17.
Maternal handling and motor development: an intracultural study 总被引:1,自引:0,他引:1
Citing a distinction between informal and formal routines used by mothers in handling their infants, we examined formal handling routines, in which the caregiver acts in a pedagogical manner; these routines are widespread in many non-Western countries. We hypothesised that formal handling serves to facilitate gross motor development during early infancy. To examine this hypothesis, the effects of a Jamaican formal handling routine on a broad range of developmental outcomes was examined. Results showed that the effects were specific to early gross motor development and in particular to postural control along the vertical axis of the body. Information is also provided on other aspects of Jamaican child care. It seems that the handling routine forms part of a folk (developmental) medicine system and may serve not only to promote child health but also as a sort of developmental neurological examination. 相似文献
18.
To study malevolent representations, earliest memories were reliably coded on scales of affect tone. Ss were diagnosed with borderline personality disorder: 31 without and 30 with concurrent major depression. Nonborderline comparison subjects had either major depressive disorder (n = 26) or no psychiatric diagnosis (n = 30). Borderline subjects were discriminated from comparison subjects by their more malevolent representations; they more frequently produced memories involving deliberate injury; and they portrayed potential helpers as less helpful. Results suggest the diagnostic significance of malevolent representations, which need to be explained by any theory of borderline personality disorder. 相似文献
19.
J M Gold C Randolph C J Carpenter T E Goldberg D R Weinberger 《Journal of abnormal psychology》1992,101(3):487-494
Effortful and automatic memory task performances were examined in 36 schizophrenic patients and 18 normal control Ss. Tasks included free recall, recognition, and frequency estimation. Patients demonstrated impairment in recall, in recognition, in semantic encoding, and in frequency estimation. Deficits were observed across tasks despite differences in attentional demands. The results suggest a basic compromise of memory function, which is consistent with recent neuroimaging evidence of structural or physiological abnormalities in frontal and temporal lobe structures in schizophrenia. 相似文献
20.