全文获取类型
收费全文 | 46711篇 |
免费 | 1960篇 |
国内免费 | 15篇 |
出版年
2020年 | 467篇 |
2019年 | 587篇 |
2018年 | 825篇 |
2017年 | 816篇 |
2016年 | 854篇 |
2015年 | 612篇 |
2014年 | 776篇 |
2013年 | 3436篇 |
2012年 | 1416篇 |
2011年 | 1449篇 |
2010年 | 896篇 |
2009年 | 875篇 |
2008年 | 1276篇 |
2007年 | 1275篇 |
2006年 | 1179篇 |
2005年 | 1074篇 |
2004年 | 1026篇 |
2003年 | 909篇 |
2002年 | 968篇 |
2001年 | 1582篇 |
2000年 | 1482篇 |
1999年 | 1107篇 |
1998年 | 532篇 |
1997年 | 457篇 |
1996年 | 458篇 |
1992年 | 861篇 |
1991年 | 835篇 |
1990年 | 838篇 |
1989年 | 802篇 |
1988年 | 774篇 |
1987年 | 748篇 |
1986年 | 747篇 |
1985年 | 807篇 |
1984年 | 661篇 |
1983年 | 607篇 |
1982年 | 493篇 |
1981年 | 455篇 |
1979年 | 718篇 |
1978年 | 531篇 |
1976年 | 477篇 |
1975年 | 599篇 |
1974年 | 689篇 |
1973年 | 695篇 |
1972年 | 563篇 |
1971年 | 543篇 |
1970年 | 500篇 |
1969年 | 559篇 |
1968年 | 685篇 |
1967年 | 597篇 |
1966年 | 564篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
942.
943.
Keith T. Poole 《Psychometrika》1984,49(3):311-323
The partial derivatives of the squared error loss function for the metric unfolding problem have a unique geometry which can be exploited to produce unfolding methods with very desirable properties. This paper details a simple unidimensional unfolding method which uses the geometry of the partial derivatives to find conditional global minima; i.e., one set of points is held fixed and the global minimum is found for the other set. The two sets are then interchanged. The procedure is very robust. It converges to a minimum very quickly from a random or non-random starting configuration and is particularly useful for the analysis of large data sets with missing entries.This paper benefits from many conversations with and suggestions from Howard Rosenthal. 相似文献
944.
Buchanan AE 《哲学与公共事务》1984,13(1):55-78
Buchanan examines, and finds inadequate, several philosophical approaches to justifying and specifying the content of a universal right to a decent minimum of health care: utilitarian arguments, Rawlsian ideal contract arguments, and Norman Daniels' equality of opportunity argument. Also rejecting the libertarian hypothesis that there is no right to a decent minimum of care, he contends that the claim that society should guarantee certain health care services can be supported by a pluralistic approach encompassing special right-claims, harm prevention, prudential arguments emphasizing public health benefits, and beneficence. 相似文献
945.
946.
The odd-even status of a sum depends on the odd-even status of its addends. A sum must be odd if an odd number of its addends are odd; else it must be even. A proposed sum that violates the required odd-even status of the sum—that is, deviates from the correct sum, whether odd or even, by an odd value (e.g., splits of ±1, ±3, ±5)—can be rejected immediately as false. Subjects in the present study did indeed use the odd-even rule in sum verification, because they were as fast and accurate in rejecting a split of ±1 as one of ±2, and a split of ±3 as one of ±4, even though a larger split generally is easier to reject (symbolic distance effect), and splits of ±3 and ±4 were rejected faster and more accurately than those of ±1 and ±2. Performance on separate odd-even tasks indicated that the odd-even properties of numbers and sums are readily available for use by adults, and that persons who do well on such tasks are especially likely to use the odd-even rule in sum verification. 相似文献
947.
Daniel S. Lee Julie A. Cederbaum Jordan P. Davis Michael S. Hurlburt Ferol E. Mennen 《Family process》2023,62(1):254-271
Maternal and adolescent depression are challenges that often co-occur. Many studies have drawn bivariate associations between maternal depressive symptoms, adolescent depressive symptoms, and family conflict, but few have examined reciprocal effects. Even among extant studies, there is a lack of clarity related to directionality of influence. Three competing theoretical models may explain the relationship between maternal depressive symptoms, adolescent depressive symptoms, and family conflict, and these processes may differ by adolescents’ sex. Using three time points of data from 187 diverse mother-adolescent dyads, we fit a taxonomy of autoregressive cross-lagged structural equation models to simultaneously evaluate the competing theoretical models and also examine differences by sex using multiple-group analyses. Results indicate a symptom-driven model whereby adolescent depressive symptoms predicted increases in family conflict. Sex differences were also found. For males, but not females, greater adolescent depressive symptoms predicted subsequent increases in maternal depressive symptoms, which then predicted lower family conflict—possibly indicating maternal disengagement/withdrawal. Our findings suggest addressing adolescent depressive symptoms in order to prevent family conflict and that distinctive targets for the prevention/intervention of family conflict should account for differences by adolescents’ sex. 相似文献
948.
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
949.
Xianqi Wang E. Scott Huebner Lili Tian 《British journal of psychology (London, England : 1953)》2023,114(4):969-990
Although several studies have addressed the relations between perceived parental warmth and social behaviours, few have distinguished their between- and within-person effects or explored their within-person mediating mechanisms. This study examined the transactional relations among perceived parental warmth (i.e. maternal warmth and paternal warmth), children's self-esteem and children's positive/negative social behaviours (i.e. prosocial behaviour and delinquent behaviour) along with the mediating role of self-esteem after disentangling between- and within-person effects. A total of 4315 Chinese elementary children (44.9% girls; Mage = 9.93 years, SD = 0.73) completed relevant measures on four occasions employing 6-month intervals. Results of random-intercept cross-lagged panel models showed that (a) perceived parental warmth reciprocally and positively predicted prosocial behaviour and self-esteem; (b) perceived paternal warmth reciprocally and negatively predicted delinquent behaviour; (c) self-esteem reciprocally predicted prosocial and delinquent behaviour; (d) perceived maternal warmth reciprocally and positively predicted prosocial behaviour through self-esteem; (e) perceived parental warmth reciprocally and negatively predicted delinquent behaviour through self-esteem; and (f) perceived maternal and paternal warmth differed in their relations with prosocial and delinquent behaviours through self-esteem. These findings illuminated the complicated longitudinal within-person interactions among perceived parental warmth, self-esteem, and social behaviours, the specific mediating mechanism of self-esteem, and the differing results associated with perceived maternal and paternal warmth, all of which yield significant implications for assessments and early interventions aimed to promote positive social behaviour. 相似文献
950.
Paula A. G. Soneral Sara E. Brownell M. Elizabeth Barnes 《Journal for the scientific study of religion》2023,62(1):184-202
Christians are notably underrepresented in science in part due to long-standing public perceptions of science-religion incompatibility and antireligious bias in science. This research explores whether undergraduates at a Christian university perceive and impose anti-Christian cultural stigma in science. Survey results from 126 biology students revealed that though students generally perceived the culture of science to be anti-Christian, they perceived Christians to have equal opportunities for scientific achievement. Results from a quasi-experimental audit study, in which students evaluated one of two profiles for mock prospective Ph.D. applicants (Christian or undisclosed faith) showed that students did not project anti-Christian stereotypes in terms of competence, hireability, or likeability, but showed some evidence of pro-Christian favorability. Together, this study suggests that the affirmational community of a Christian University may alleviate some negative impacts of anti-Christian stereotypes in academic biology, even as students perceive discrimination against Christians in science and atheists as more scientifically competent. 相似文献