全文获取类型
收费全文 | 2011篇 |
免费 | 62篇 |
出版年
2023年 | 7篇 |
2022年 | 7篇 |
2021年 | 19篇 |
2020年 | 23篇 |
2019年 | 26篇 |
2018年 | 54篇 |
2017年 | 46篇 |
2016年 | 54篇 |
2015年 | 43篇 |
2014年 | 43篇 |
2013年 | 234篇 |
2012年 | 76篇 |
2011年 | 88篇 |
2010年 | 58篇 |
2009年 | 66篇 |
2008年 | 78篇 |
2007年 | 90篇 |
2006年 | 69篇 |
2005年 | 78篇 |
2004年 | 78篇 |
2003年 | 71篇 |
2002年 | 69篇 |
2001年 | 34篇 |
2000年 | 32篇 |
1999年 | 28篇 |
1998年 | 34篇 |
1997年 | 29篇 |
1996年 | 31篇 |
1995年 | 28篇 |
1994年 | 31篇 |
1993年 | 32篇 |
1992年 | 24篇 |
1991年 | 17篇 |
1990年 | 29篇 |
1989年 | 30篇 |
1988年 | 29篇 |
1987年 | 18篇 |
1986年 | 17篇 |
1985年 | 20篇 |
1984年 | 26篇 |
1983年 | 20篇 |
1982年 | 26篇 |
1981年 | 24篇 |
1980年 | 19篇 |
1979年 | 9篇 |
1978年 | 23篇 |
1977年 | 10篇 |
1976年 | 18篇 |
1975年 | 15篇 |
1973年 | 11篇 |
排序方式: 共有2073条查询结果,搜索用时 250 毫秒
21.
Patricia H. Werhane 《Theoretical medicine and bioethics》1984,5(3):359-363
The recent Supreme Court decision upholding Roe v. Wade and in particular, the dissent by Justice Sandra Day O'Connor, sheds new light on the issue of abortion. Let us consider any stage of a pregnancy when abortion is medically safe for the mother. If at that stage it is also medically viable to save the fetus, is an abortion performed at that stage of pregnancy morally justifiable? For example, if it is, or becomes, medically safe to perform abortions after first trimester of pregnancy and at the same time saving a fetus is, or becomes, medically viable or not unusual during some stage of the second trimester, can abortions during and after that stage of pregnancy be justified? With a number of qualifications I shall argue the thesis that as a general rule, but not an absolute rule, abortion in these instances is not usually justifiable. For if it is, then one will also have to grant the moral justification for a number of other highly questionable medical practices. This thesis is not to be identified with the stronger claim that abortions of viable fetuses can never be performed. There are surely exceptions such as when the life or health of the mother is in danger. But, I shall argue, the justification for making such exceptions is on different grounds than is sometimes claimed because one must weigh the health of the mother against the life of another human being. 相似文献
22.
Patricia A. Harrington 《Journal of religion and health》1984,23(3):204-217
This essay uses Freud to interpret the symbolism and theology of Mary in modern Catholicism. In her role as the mother of believers, Mary functions to place the Christian in the position of a child who receives illusory gratification from the mother. In her role as model for Christians to emulate, Mary functions to place the Christian in the position of receptivity and dependence which Freud associated with femininity. Reinterpreting Freud from a feminist perspective, I suggest that the kind of femininity Mary represents serves to perpetuate patriachal social structures and to inhibit full psychological maturity. 相似文献
23.
Two versions of a distributed-memory model, one for associative information and one for serial-order information, leave open the question of whether there are two different modes of operation or only one. An analysis of these two versions showed that differential predictions emerge when one considers the role of item information. To test these predictions, a standard item-recognition task (Sternberg, 1966) was embedded in a paired-associate probe-recognition task, a serial-order probe-recognition task, or both. The item-recognition serial-position curves were quite different in the paired-associate and the serial-order conditions, and followed the paired-associate condition when the two were combined. In general, the results were consistent with the predictions of the distributed-memory models, and supported the idea of different modes of operation rather than a single common mode of operation. 相似文献
24.
25.
This article presents a series of studies investigating the influence of experimental factors and the personological variables of age and sex upon spatial abilities. It was hypothesized that the overall equivocal findings typical of spatial research may be partially due to the use of different factors across studies. The experimental variables of spatial factor, task demands, spatial information type, information-processing mode, and response mode were systematically manipulated across the eight studies. In each individual analysis of data collected in a specific study, no significant main effect sex differences were detected. However, when a meta-analytic review of the studies was conducted, both spatial information dimensionality and information dimensionality × spatial factor assessed proved to be influential on male and female spatial performances. Female performance was superior when the dimensionality of stimulus and response variables was invariant. Males had the advantage when dimensionality crossing was necessitated. The discrepancy between the sexes was particularly dramatic when the spatial orientation factor was tapped. 相似文献
26.
Sarah B. Woods Angela Hiefner Patricia N. E. Roberson Nida Zahra Elizabeth Mayfield Arnold Victoria Udezi 《Family process》2023,62(1):230-253
African Americans are at significantly greater risk of hypertension and worse cardiovascular outcomes than other racialized groups, yet hypertension intervention effects remain limited. Thus, it is necessary to understand the potential mechanisms whereby interventions may be more effectively targeted to improve health. Supported by prior research evidence and guided by the Biobehavioral Family Model, this study examined associations between family relationship quality, psychological wellbeing, and self-management behaviors for African Americans with hypertension. Data were pooled from three Midlife Development in the U.S. projects, resulting in a sample of 317 African Americans (63.4% female, Mage = 53.32) with self-reported high blood pressure in the past 12 months. We tested four cross-sectional multiple mediator models, with depressed mood and environmental mastery mediating associations between family strain and exercise, smoking, problematic alcohol use, and stress-eating. Environmental mastery mediated the association between greater family strain and decreased odds of achieving recommended exercise levels; greater odds of reporting problematic alcohol use; and greater stress-eating. Though family strain was associated with depressed mood in each model, this variable did not serve as an indirect pathway to self-management behaviors. Family strain, and the potential pathway identified via environmental mastery, may be a meaningful predictor of disease self-management for African Americans with hypertension. Longitudinal studies are needed to examine directionality and to support intervention trials for improving self-management and hypertension outcomes. 相似文献
27.
28.
Patricia M. Blough 《Attention, perception & psychophysics》1972,12(4):342-348
This three-part study describes wavelength generalization gradients around a series of training wavelengths ranging from 480 to 645 om. Luminance was controlled for the pigeon’s spectral sensitivity. The response measure was probability of keypecking during a 2-sec stimulus presentation. Both an extinction procedure, where stimulus wavelengths occurred in 15-nm steps, and a maintained discrimination procedure, where step size was 2 to 4 nm, were used to obtain gradients. During a portion of the maintained discrimination procedure, new luminances were introduced, so that the effect of luminance level on gradient slope could be examined. Comparison of the resulting functions across training wavelengths revealed: (1) consistent differences in gradient slope in different spectral regions and (2) an increase in slope with luminance increase. The findings are related to recent electroretinographic wavelength contrast data and to psychophysical measures of wavelength discriminability. 相似文献
29.
The effects of unavoidable shocks on a multiple schedule having an avoidance component 总被引:1,自引:1,他引:0
下载免费PDF全文
![点击此处可从《Journal of the experimental analysis of behavior》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Marcus B. Waller Patricia F. Waller 《Journal of the experimental analysis of behavior》1963,6(1):29-37
Two dogs were maintained on a multiple schedule having both a food reinforced and an avoidance component (Mult VI 1′ SΔ AvoidSS20 RS20 SΔ). The effects of superimposing an Estes-Skinner procedure for delivering unavoidable shocks on all components of the multiple schedule were observed. The buzzer-shock pairing of the Estes-Skinner procedure produced an increased rate of responding on the avoidance component of the schedule and also on the SΔ components. No persistent change in rate was observed on the food component during the pre-shock stimulus. Control performances on all components could be regained by either extinguishing or eliminating the buzzer-shock pairing. Extinction of the avoidance responding had little effect on the increased rates of responding produced by the Estes-Skinner procedure on the SΔ and avoidance extinction components and did not lead to a conditioned suppression of the food reinforced responding. Rate of responding during the pre-shock stimulus was observed to be relatively independent of changes in the maintaining schedules. Responding during the pre-shock stimulus could be conditioned and maintained after an extensive history of avoidance extinction. 相似文献
30.