首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1581篇
  免费   112篇
管理学   92篇
民族学   7篇
人才学   1篇
人口学   149篇
丛书文集   10篇
理论方法论   253篇
综合类   17篇
社会学   1066篇
统计学   98篇
  2023年   21篇
  2022年   7篇
  2021年   14篇
  2020年   53篇
  2019年   55篇
  2018年   78篇
  2017年   106篇
  2016年   83篇
  2015年   53篇
  2014年   48篇
  2013年   294篇
  2012年   70篇
  2011年   74篇
  2010年   49篇
  2009年   43篇
  2008年   67篇
  2007年   62篇
  2006年   64篇
  2005年   54篇
  2004年   59篇
  2003年   38篇
  2002年   37篇
  2001年   32篇
  2000年   16篇
  1999年   14篇
  1998年   15篇
  1997年   13篇
  1996年   9篇
  1995年   10篇
  1994年   15篇
  1993年   19篇
  1992年   10篇
  1991年   6篇
  1990年   12篇
  1989年   6篇
  1988年   7篇
  1987年   6篇
  1986年   8篇
  1985年   8篇
  1984年   10篇
  1983年   9篇
  1982年   2篇
  1981年   10篇
  1980年   5篇
  1979年   3篇
  1978年   3篇
  1975年   4篇
  1974年   2篇
  1967年   2篇
  1965年   2篇
排序方式: 共有1693条查询结果,搜索用时 15 毫秒
131.
Quantitative Approaches in Use to Assess Cancer Risk   总被引:4,自引:0,他引:4  
  相似文献   
132.
Urban forests and herbaceous open space play a vital role in the environmental and aesthetic health of cities, yet they are rarely identified in land-use inventories of urban areas. To provide information on urban forests and other vegetative land cover in Illinois cities, Landsat Thematic Mapper (TM) data from June 27, 1988, were classified for the Chicago metropolitan region (9,717 km2). Ten land-cover classes were identified, including two types of forestland (occupying 5.8% of the total area), residential land with trees (14.6%) or without trees (7.8%), cropland (37.5%), two types of grassland (7.7%), urban with impervious surfaces (23.1%), water (1.6%), and miscellaneous vegetation (2.1%). Correlation analyses indicated that household income and household density are strongly related to land covers in the region, particularly those with tree cover and urbanized land. Population changes for 1980–1985 and 1985–2010 (projected) show a pattern of increasing density in the urbanized zone concurrent with continued urban sprawl, primarily into current cropland.  相似文献   
133.
Mixed Levels of Uncertainty in Complex Policy Models   总被引:3,自引:0,他引:3  
The characterization and treatment of uncertainty poses special challenges when modeling indeterminate or complex coupled systems such as those involved in the interactions between human activity, climate and the ecosystem. Uncertainty about model structure may become as, or more important than, uncertainty about parameter values. When uncertainty grows so large that prediction or optimization no longer makes sense, it may still be possible to use the model as a behavioral test bed to examine the relative robustness of alternative observational and behavioral strategies. When models must be run into portions of their phase space that are not well understood, different submodels may become unreliable at different rates. A common example involves running a time stepped model far into the future. Several strategies can be used to deal with such situations. The probability of model failure can be reported as a function of time. Possible alternative surprises can be assigned probabilities, modeled separately, and combined. Finally, through the use of subjective judgments, one may be able to combine, and over time shift between models, moving from more detailed to progressively simpler order-of-magnitude models, and perhaps ultimately, on to simple bounding analysis.  相似文献   
134.
135.
Correspondence to: Professor Colin Pritchard, Department of Mental Health, School of Medicine, Southampton University, Royal South Hants Hospital, Southampton SO14 0YG, UK. E-mail: cp1{at}soton.ac.uk Summary The study compares Mental-Disorder-Related (MDR) suicide rateswith Child-Sex-Abuse-Related (CSAR) suicide of ‘Victims’and ‘Perpetrators’ of child sex abuse, based uponan examination of all Coroners’ inquest files over a six-yearperiod (n = 1,017). Census data, psychiatric case register andpolice records were used to calculate the potential MDR andCSAR populations. There were five main findings: (i) male andfemale CSAR victim suicide rates were 2.2. and 2.5 times theGeneral Population Suicide Rate (GPSR), respectively; (ii) everyfemale, and 80 per cent of male CSAR victim suicides, also hada mental disorder but none of the CSAR perpetrator suicides;(iii) male and female MDR suicide rates were 5 and 6 times theCSAR Victim rates; (iv) the sex abuser perpetrators’ suiciderate was more than 3 times the male MDR rate; (v) the intra-and extra-familial perpetrator suicide rates, were 25 and 78times the GPSR, respectively. Possible explanations for thesesurprising results are briefly discussed. They confirm the overrepresentationof people with mental disorder amongst suicides, and identifyan overrepresentation of CSAR suicides, particularly perpetrators.The results have implications for suicide prevention programmes,whilst highlighting the importance of the child protection-psychiatricinterface, and indicates the futility of simple explanationsin an area of practical and moral complexity.  相似文献   
136.
Few studies have examined academic researchers' understandings or attitudes toward conflict of interest policies even though these understandings and attitudes represent a crucial component of both compliance and educational efforts. This study reports the results of a large-scale, cross-sectional survey of research faculty at the nine campuses of the University of California regarding their understandings of and attitudes toward campus conflict of interest policies. We gathered information on their general assessments of investigators with financial ties to industry sponsors and reactions to the process of implementing conflict of interest policies at their respective campuses. We surveyed 1,971 faculty members from the nine-campus University of California system and had 779 responses (39% response rate). The sampled faculty were in the ten departments with the most number of financial disclosures at each campus. We utilized the WebSurveyor software to create a secure, online, 21-item survey. Our study reveals faculty with complex, sometimes contradictory, feelings about academic-industry relationships and highlights perceived gaps in policy and process. Most respondents were concerned about unlimited financial relationships, but a sizable number also viewed campus policies as irrelevant. Some expressed considerable anger over the process of policy implementation, rejecting the policies on the basis of professional and individual self-determination and moral integrity. Our study suggests the need for renewed efforts to encourage awareness of the relevance of conflict of interest policies for all faculty, new efforts to increase understanding of the situational nature of conflicts of interest, and reexamination of the processes of policy implementation at the campus level.  相似文献   
137.
Women's reproductive biology imposes heavy obligatory costs of parental investment, creating strong selective forces hypothesized to shape female mating psychology around critical decisions such as the choice of partner, the timing of sexual intercourse, and the timing of reproduction. We propose that female sexual desire has evolved as one adaptation among several designed to regulate these decisions. We hypothesize (a) an increase in desire as conception probability increases, but only among women who are in committed long-term relationships; and (b) a shift in the desire for a primary partner as compared with extra-pair partners as ovulation approaches, dependent upon a woman's evaluation of her primary partner's relative quality. We tested several predictions derived from these hypotheses in a study of 173 women who were not taking oral contraceptives. Results confirmed Hypothesis 1: An ovulatory peak in sexual desire was found only for mated women; for unmated women, conception probability and sexual desire were uncorrelated. Hypothesis 2 was partially supported. Among mated women, those with higher conception probability exhibited higher levels of in-pair sexual desire relative to those at lower conception probability. Conception probability and relationship length interacted significantly to predict extra-pair desires, such that women in longer relationships were more likely to experience desire for extra-pair partners during periods of high conception probability. The pursuit of an in-pair conceptive strategy (as opposed to an extra-pair conceptive strategy) was also associated with the occurrence of sexual activity in the relationship.  相似文献   
138.
Three hundred and sixty-eight parents shared their perceptions of special-needs adoption preparation. Utilizing both quantitative and qualitative data to determine and understand what factors contribute to preparation, this study found that 12 child, family, and agency variables were correlated with perceived preparation, and that parents perceived level of preparation was predicted by the childs ability to attach, by the parents relationship with the agency, by the duration of the adoption, and by the parents ages at the time of adoption. Implications of these findings are discussed, as they relate to supporting parents, children, and families in special-needs adoptive placements.  相似文献   
139.
Reducing non-marital childbearing and making nonresidential fathers take greater responsibility for their children were identified as goals of numerous policy changes since the 1980s. Child-support award rates for children born to unmarried parents have been quite low historically, leading lawmakers to focus on increasing both award and payment rates for this group. Nonmarital fathers are also much less likely to have contact with their children. Although evidence suggests that policy efforts increase child support awards and receipt, the link between child support policies, child support outcomes, and father-child contact has received less attention. This paper uses data from the Survey of Income and Program Participation on children born between 1985–1997 to investigate the relationship between child-support award and receipt and the amount of contact that fathers have with their non-residential children. Since it is likely that both of these behaviors are, in part, determined by unobservable characteristics of the father, we estimate an instrumental variables Tobit model. The model is identified by our assumption that child support policy variables can impact child support awards and payments, but father-child contact cannot be directly legislated. Our results suggest that there are unintended, but desirable effects of child support establishment and collection. Policies to collect child support not only increase financial resources to families, but through their impact on payments increase visitation and contact between these children and their fathers. The estimated impact of receiving child support on contact is more than 27 days per year.An earlier version of this paper was presented at the Annual Meetings of the American Economic Association, Washington DC, January 2003 and the Annual Meetings of the Association of Public Policy and Management, November 2003. Support from NICHD Grant # HD30944 is gratefully acknowledged. We would like to thank Suzann Eshleman for excellent computer programming and James Scully for providing us with data on genetic testing laws.  相似文献   
140.
This is an empirical study of the relationship between aesthetic evaluation, collective action, and artistic success. Documentary evidence is examined to show that the initial artistic success of Jackson Pollock, the leading painter in the early years of Abstract Expressionism, was not due to coherent aesthetic evaluation by the New York art world. Secondary sources are then reviewed and it is suggested that Pollock's rise to artistic preeminence was brought about directly by collective action in the form of a promotional campaign on the part of a small, but influential, group of actors closely associated with the artist.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号