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   5871篇
  免费   82篇
管理学   810篇
民族学   18篇
人才学   7篇
人口学   552篇
丛书文集   17篇
理论方法论   519篇
综合类   63篇
社会学   2708篇
统计学   1259篇
  2023年   32篇
  2021年   37篇
  2020年   76篇
  2019年   118篇
  2018年   125篇
  2017年   187篇
  2016年   122篇
  2015年   86篇
  2014年   106篇
  2013年   997篇
  2012年   208篇
  2011年   155篇
  2010年   118篇
  2009年   110篇
  2008年   130篇
  2007年   139篇
  2006年   127篇
  2005年   128篇
  2004年   133篇
  2003年   91篇
  2002年   123篇
  2001年   141篇
  2000年   113篇
  1999年   129篇
  1998年   112篇
  1997年   107篇
  1996年   81篇
  1995年   82篇
  1994年   101篇
  1993年   84篇
  1992年   95篇
  1991年   82篇
  1990年   89篇
  1989年   82篇
  1988年   96篇
  1987年   88篇
  1986年   78篇
  1985年   91篇
  1984年   73篇
  1983年   76篇
  1982年   71篇
  1981年   63篇
  1980年   58篇
  1979年   76篇
  1978年   63篇
  1977年   52篇
  1976年   64篇
  1975年   61篇
  1974年   38篇
  1973年   38篇
排序方式: 共有5953条查询结果,搜索用时 15 毫秒
221.
222.
In this paper, five alternative advertising policies that belong to the advertising pulsation class are compared analytically for linear and concave response functions using a modified version of the Vidale-Wolfe model. The results of the research show that (1) For both linear and concave response functions, advertising pulsing/maintenance policy dominates advertising pulsing policy but is dominated by the Uniform Advertising Policy. For convex response functions, the order of dominance is reversed. (2) For linear response functions, uniform advertising policy dominates the impulse advertising policy but is dominated by the chattering advertising policy. (3) For concave response functions, uniform advertising policy dominates both the impulse advertising policy and the chattering advertising policy. (4) For convex response functions, chattering advertising policy dominates both the advertising pulsing policy and the impulse advertising policy. The Vidale-Wolfe model is estimated using the well-known Lydia Pinkham data. Optimality analysis shows that the company was overadvertising about half of the time studied. Overadvertising seems to have produced appreciable gain in sales and created significant barriers to competitive entry at a little cost in terms of foregone profits.  相似文献   
223.
This article describes three experiments that investigate the impact of data presentation on framing, which is the differential evaluation of objectively equivalent information given different frames of reference. The experiments were designed to vary the amount of information and the format of presentation (tables versus graphs) provided to the decision maker to gain an understanding of the mechanism underlying framing. The inferred information model proposed by Johnson and Levin [11] is utilized to explain the results of the three experiments in terms of the redistribution of weights attached by the decision makers to the attributes of the prospective outcomes. The results of the three experiments indicate that framing effects are observed only when the presentation of data facilitates the shifting of weights among the attributes of the available alternatives. The results further indicate that framing is eliminated as more information is displayed. However, presentation of additional information does not eliminate framing when a graphical format is utilized. Finally, no framing effects are observed when uneven amounts of information are used to describe two alternatives in the same decision task.  相似文献   
224.
The persistent shortage of nurses adversely affects the productivity, quality of care, and operating costs in most acute care hospitals. Aggravating the shortage are high nurse turnover rates, approaching 200% in some institutions. Policies to ensure adequate staffing levels and provide more attractive work schedules are alleged to improve nurse retention. However, their cost is seldom discussed. We compared expected nursing expense and workforce requirements to staff eight medical and surgical nursing units of a large hospital for 1 month, under 12 different scheduling policies alleged to improve turnover. Using simulation and an integrated staffing and scheduling methodology, we found that the expected nursing wages and workforce requirements for some policies differed by as much as 33%. In this hospital, the expected labor costs for certain policies could erode the benefits expected from improved retention. In contrast, other policies appear to allow high utilization of nursing resources, enhancing the expected benefits of reduced turnover with significant reductions in expenses for labor, recruiting, training, and fringe benefits.  相似文献   
225.
R. J. Reynolds Tobacco USA (RJR) is currently implementing a microcomputer-based decision support system to computerize and optimize the selection of patterns for loading cases of finished product into truck trailers at RJR's Central Distribution Center. This system allows for the efficient loading of trucks with less supervision. Total annual savings from reduced personnel and shipping costs is approximately $850,000. In addition to these benefits, the system is a stepping stone for trailer loading automation and the integration of a comprehensive load planning system.  相似文献   
226.
Between 1898 and 1934, in synchronous and successive U.S. military interventions and occupations in Cuba, Puerto Rico, the Philippines, Haiti, and the Dominican Republic, American soldiers made public works, and especially roads, into a global technology of imperial power. This essay examines infrastructure as a factor in state formation and capitalist transition in these five different imperial spaces as a way to study U.S. empire, and its effects on foreign societies, through a comparative, global, and intra‐imperial approach often precluded by the methodological nationalism of historical and sociological literatures. Despite significant differences between these sites of U.S. war and occupation, both prior to American interventions and during them, U.S. military public works expressed and advanced a common political‐economic logic of state centralization and capital accumulation. Colonial and post‐colonial political institutions and political economies, the strength of central governments, the extent of plantation agriculture and rural proletarianization, world commodity markets, and geography and natural events varied, but determined U.S. imperial infrastructure's outcomes. By the 1930s, the U.S. military had elevated infrastructural improvement to a key repertoire of American imperial power in the world, and one which persisted as the United States turned away from formal colonialism in the era of the Cold War and decolonization.  相似文献   
227.
Urban Ecosystems - Generalist wildlife species often thrive in urban environments because of increased anthropogenic resources. However, human-wildlife interactions, especially if negative, raise...  相似文献   
228.
To perform variable selection in expectile regression, we introduce the elastic-net penalty into expectile regression and propose an elastic-net penalized expectile regression (ER-EN) model. We then adopt the semismooth Newton coordinate descent (SNCD) algorithm to solve the proposed ER-EN model in high-dimensional settings. The advantages of ER-EN model are illustrated via extensive Monte Carlo simulations. The numerical results show that the ER-EN model outperforms the elastic-net penalized least squares regression (LSR-EN), the elastic-net penalized Huber regression (HR-EN), the elastic-net penalized quantile regression (QR-EN) and conventional expectile regression (ER) in terms of variable selection and predictive ability, especially for asymmetric distributions. We also apply the ER-EN model to two real-world applications: relative location of CT slices on the axial axis and metabolism of tacrolimus (Tac) drug. Empirical results also demonstrate the superiority of the ER-EN model.  相似文献   
229.
230.
Lot streaming is the process of splitting a job into sublots so its operations can be overlapped and its progress accelerated. We present a computationally efficient procedure for solving the m-machine, two-sublot problem, and we discuss the bottleneck insights that emerge from the analysis. We also examine heuristic approaches for more than two sublots and discuss computational results for these procedures.  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