全文获取类型
收费全文 | 12517篇 |
免费 | 242篇 |
专业分类
管理学 | 1781篇 |
民族学 | 61篇 |
人才学 | 1篇 |
人口学 | 1246篇 |
丛书文集 | 67篇 |
教育普及 | 1篇 |
理论方法论 | 1069篇 |
现状及发展 | 1篇 |
综合类 | 139篇 |
社会学 | 6083篇 |
统计学 | 2310篇 |
出版年
2023年 | 84篇 |
2021年 | 66篇 |
2020年 | 181篇 |
2019年 | 258篇 |
2018年 | 291篇 |
2017年 | 402篇 |
2016年 | 319篇 |
2015年 | 218篇 |
2014年 | 276篇 |
2013年 | 2205篇 |
2012年 | 434篇 |
2011年 | 354篇 |
2010年 | 292篇 |
2009年 | 278篇 |
2008年 | 307篇 |
2007年 | 307篇 |
2006年 | 291篇 |
2005年 | 290篇 |
2004年 | 275篇 |
2003年 | 255篇 |
2002年 | 275篇 |
2001年 | 311篇 |
2000年 | 304篇 |
1999年 | 293篇 |
1998年 | 195篇 |
1997年 | 178篇 |
1996年 | 170篇 |
1995年 | 178篇 |
1994年 | 151篇 |
1993年 | 162篇 |
1992年 | 182篇 |
1991年 | 153篇 |
1990年 | 169篇 |
1989年 | 194篇 |
1988年 | 162篇 |
1987年 | 146篇 |
1986年 | 159篇 |
1985年 | 177篇 |
1984年 | 175篇 |
1983年 | 165篇 |
1982年 | 130篇 |
1981年 | 112篇 |
1980年 | 107篇 |
1979年 | 147篇 |
1978年 | 98篇 |
1977年 | 91篇 |
1976年 | 93篇 |
1975年 | 87篇 |
1974年 | 84篇 |
1973年 | 76篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
This paper analyses how network embeddedness affects the exploration and exploitation of R&D project performance. By developing joint projects, partners and projects are linked to one another and form a network that generates social capital. We examine how the location, which determines the access to information and knowledge within a network of relationships, affects the performance of projects. We consider this question in the setup of exploration and exploitation projects, using a database built from an EU framework. We find that each of the structural embeddedness dimensions (degree, betweenness and eigenvector centrality) have a different impact on the exploration and exploitation project performance. Our empirical analysis extends to project management literature and social capital theory, by including the effect that the acquisition of external knowledge has on the performance of the project. 相似文献
102.
Lawrence W.C. Lai K. W. Chau Frank T. Lorne Weisheng Lu 《Planning Practice and Research》2020,35(1):51-61
ABSTRACTInformed by a Coasian transaction cost paradigm enriched by the concept of Schumpeterian innovations, this paper discusses the advantages of using experimental coastal reclamation of the sea to build new cities with a policy for fostering innovations. A new development area at the margin of Shenzhen in China, Qianhai, is used to demonstrate how urban expansion by urban sprawling in a megacity can be avoided by reclamation of marginal land as analytically less costly than along intra-marginal land and more suitable for experimentation for the type of megacity concept that Qianhai aims to achieve. 相似文献
103.
Perry C. Oddo Ben S. Lee Gregory G. Garner Vivek Srikrishnan Patrick M. Reed Chris E. Forest Klaus Keller 《Risk analysis》2020,40(1):153-168
Sea levels are rising in many areas around the world, posing risks to coastal communities and infrastructures. Strategies for managing these flood risks present decision challenges that require a combination of geophysical, economic, and infrastructure models. Previous studies have broken important new ground on the considerable tensions between the costs of upgrading infrastructure and the damages that could result from extreme flood events. However, many risk-based adaptation strategies remain silent on certain potentially important uncertainties, as well as the tradeoffs between competing objectives. Here, we implement and improve on a classic decision-analytical model (Van Dantzig 1956) to: (i) capture tradeoffs across conflicting stakeholder objectives, (ii) demonstrate the consequences of structural uncertainties in the sea-level rise and storm surge models, and (iii) identify the parametric uncertainties that most strongly influence each objective using global sensitivity analysis. We find that the flood adaptation model produces potentially myopic solutions when formulated using traditional mean-centric decision theory. Moving from a single-objective problem formulation to one with multiobjective tradeoffs dramatically expands the decision space, and highlights the need for compromise solutions to address stakeholder preferences. We find deep structural uncertainties that have large effects on the model outcome, with the storm surge parameters accounting for the greatest impacts. Global sensitivity analysis effectively identifies important parameter interactions that local methods overlook, and that could have critical implications for flood adaptation strategies. 相似文献
104.
David J. Yu Michael L. Schoon Jason K. Hawes Seungyoon Lee Jeryang Park P. Suresh C. Rao Laura K. Siebeneck Satish V. Ukkusuri 《Risk analysis》2020,40(8):1509-1537
Maintaining the performance of infrastructure-dependent systems in the face of surprises and unknowable risks is a grand challenge. Addressing this issue requires a better understanding of enabling conditions or principles that promote system resilience in a universal way. In this study, a set of such principles is interpreted as a group of interrelated conditions or organizational qualities that, taken together, engender system resilience. The field of resilience engineering identifies basic system or organizational qualities (e.g., abilities for learning) that are associated with enhanced general resilience and has packaged them into a set of principles that should be fostered. However, supporting conditions that give rise to such first-order system qualities remain elusive in the field. An integrative understanding of how such conditions co-occur and fit together to bring about resilience, therefore, has been less clear. This article contributes to addressing this gap by identifying a potentially more comprehensive set of principles for building general resilience in infrastructure-dependent systems. In approaching this aim, we organize scattered notions from across the literature. To reflect the partly self-organizing nature of infrastructure-dependent systems, we compare and synthesize two lines of research on resilience: resilience engineering and social-ecological system resilience. Although some of the principles discussed within the two fields overlap, there are some nuanced differences. By comparing and synthesizing the knowledge developed in them, we recommend an updated set of resilience-enhancing principles for infrastructure-dependent systems. In addition to proposing an expanded list of principles, we illustrate how these principles can co-occur and their interdependencies. 相似文献
105.
106.
R W Hart S C Freni D W Gaylor J R Gillette L K Lowry J M Ward E K Weisburger P Lepore A Turturro 《Risk analysis》1986,6(2):117-154
The Color Additives Scientific Review Panel considered whether there was information sufficient to perform a carcinogenic risk assessment on the colors D&C Red No. 19 (R-19), D&C Red No. 37 (R-37), D&C Orange No. 17 (O-17), D&C Red No. 9 (R-9), D&C Red No. 8 (R-8) and FD&C Red No. 3 (R-3) and to evaluate the assessments sent to FDA as part of the petitions for use of the colors for drug and external uses by the Cosmetic, Toiletry and Fragrance Association (CTFA). There is a lack of human data concerning the colors for making a human health assessment, so the assessments are based upon the extrapolation of animal data. The risk assessments are determined for exposure to single chemicals. Excluded from consideration are possible effects from exposure to multiple chemicals, such as co-carcinogenesis, promotion, synergism, antagonism, etc. In the light of recent efforts in establishing a consensus in risk assessment, the Panel has determined that the CTFA assessments for R-10, O-17, and R-9 are consistent with present acceptable usages, although it questions some of the assumptions used in the assessments. The Panel identified a number of general assumptions made, and discusses their validity, their impact on total uncertainty, and the potential options to address the gaps in understanding that necessitate the assumption. The Panel also derived revised risk estimates using more "reasonable" assumptions than "worst-case" situations, for 90th percentile and average exposure. For those assumptions that are easily quantifiable, the Panel's estimates are less than an order of magnitude lower than the CTFA risk estimates, indicating that the underestimates and overestimates of the CTFA risk estimates tend to balance each other. The impact of most of the assumptions is not quantifiable. The assessment for R-3 is complicated by the fact that there is no good skin penetrance study for this color. It was assumed that the penetrance is similar to that of another water-soluble xanthene color, R-19. It is expected that the absorption of the color is not likely to exceed that of the smaller molecule, R-19. Therefore, the risk estimates are similar to the CTFA estimates, but with different reasoning. The estimates for R-8 and R-37 are different from the others in that there is a lack of any exposure or toxicological information on these colors.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
107.
Hagerty Michael R. Cummins Robert A. Ferriss Abbott L. Land Kenneth Michalos Alex C. Peterson Mark Sharpe Andrew Sirgy Joseph Vogel Joachim 《Social indicators research》2001,55(1):1-96
A number of governments and public policy institutes have developed Quality of Life Indexes – statistics that attempt to measure the quality of life for entire states or regions. We develop 14 criteria for determining the validity and usefulness of such QOL indexes to public policy. We then review 22 of the most-used QOL indexes from around the world. We conclude that many of the indexes are successful in that they are reliable, have established time series measures, and can be disaggregated to study subpopulations. However, many fall short in four areas: (1) indexes vary greatly in their coverage and definitions of domains of QOL, (2) none of the indexes distinguish among the concepts of input, throughput, and output that are used by public policy analysts, (3) they fail to show how QOL outputs are sensitive to public policy inputs, and (4) none have examined convergent validity against each other. We conclude that many of these indexes are potentially very useful for public policy and recommend research to further improve them. 相似文献
108.
Neighborhood disadvantage, stress, and drug use among adults 总被引:1,自引:0,他引:1
Boardman JD Finch BK Ellison CG Williams DR Jackson JS 《Journal of health and social behavior》2001,42(2):151-165
This paper explores the relationships among neighborhood disadvantage, stress, and the likelihood of drug use in a sample of adults (N = 1,101). Using the 1995 Detroit Area Study in conjunction with tract-level data from the 1990 census, we find a positive relationship between neighborhood disadvantage and drug use, and this relationship remains statistically significant net of controls for individual-level socioeconomic status. Neighborhood disadvantage is moderately associated with drug related behaviors, indirectly through increased social stressors and higher levels of psychological distress among residents of disadvantaged neighborhoods. A residual effect of neighborhood disadvantage remains, net of a large number of socially relevant controls. Finally, results from interactive models suggest that the relationship between neighborhood disadvantage and drug use is most pronounced among individuals with lower incomes. 相似文献
109.
The impact of childhood abuse and neglect on adult mental health: a prospective study 总被引:10,自引:0,他引:10
This paper examines the impact of three types of victimization in childhood--sexual abuse, physical abuse, and neglect--on lifetime measures of mental health among adults. In contrast to research that relies on retrospective recall of childhood victimization, this work uses a prospective sample gathered from records of documented court cases of childhood abuse and neglect in a midwestern city around 1970. These subjects were interviewed about twenty years later. In addition, this research compares outcomes of the 641 members of the abuse and neglect group with a matched control group of 510 persons who did not have documented cases of abuse or neglect. The results indicate that men who were abused and neglected as children have more dysthymia and antisocial personality disorder as adults than matched controls, but they did not have more alcohol problems. Abused and neglected women report more symptoms of dysthymia, antisocial personality disorder, and alcohol problems than controls. After controlling for stressful life events, however, childhood victimization had little direct impact on any lifetime mental health outcome. This research indicates the importance of adopting an approach that places childhood victimization in the context of other life stressors and of prospective changes over the life course. 相似文献
110.