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   6754篇
  免费   987篇
  国内免费   23篇
管理学   1190篇
民族学   14篇
人口学   72篇
丛书文集   166篇
理论方法论   854篇
综合类   1183篇
社会学   1681篇
统计学   2604篇
  2024年   6篇
  2023年   21篇
  2022年   14篇
  2021年   115篇
  2020年   199篇
  2019年   421篇
  2018年   301篇
  2017年   509篇
  2016年   408篇
  2015年   388篇
  2014年   445篇
  2013年   1118篇
  2012年   546篇
  2011年   378篇
  2010年   352篇
  2009年   252篇
  2008年   311篇
  2007年   237篇
  2006年   229篇
  2005年   213篇
  2004年   232篇
  2003年   197篇
  2002年   221篇
  2001年   185篇
  2000年   144篇
  1999年   59篇
  1998年   35篇
  1997年   38篇
  1996年   29篇
  1995年   24篇
  1994年   14篇
  1993年   17篇
  1992年   20篇
  1991年   14篇
  1990年   16篇
  1989年   5篇
  1988年   9篇
  1987年   4篇
  1986年   3篇
  1985年   8篇
  1984年   4篇
  1983年   7篇
  1982年   5篇
  1981年   2篇
  1980年   2篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   2篇
排序方式: 共有7764条查询结果,搜索用时 15 毫秒
991.
Mass customization has been viewed as desirable but difficult to achieve in the volume automotive sector. Here we consider flexibility in automotive order fulfillment systems to enhance the ability to satisfy customers with their desired vehicle variants within acceptable delivery lead times. Two types of flexibility are compared in a Virtual‐Build‐to‐Order system—reconfiguration in the planning pipeline and interdealer trading. A representative simulation model is used to investigate the impact of the two types of flexibility across a wide spectrum of product variety levels. The impacts on major stakeholders in the system—the producer, dealers, and customers—are considered. The study shows that both types of flexibilities can bring significant benefits in terms of reductions in lead time and inventory holding. The level of product variety strongly influences the observed effects—an important finding in the mass customization context. Upstream reconfiguration flexibility brings greater benefits than downstream trading flexibility. Reconfiguration tends to dominate trading as a fulfillment mechanism when both are in operation. The findings have implications for the design and management of automotive order fulfillment systems in improving their ability to offer mass customization. The study has relevance for companies in other sectors with high levels of variety that seek to combine efficiency, speed, and flexibility in order fulfillment.  相似文献   
992.
长期以来训诂学界存在着训诂学性质之争,众多的训诂学著作时常发生"撞车"的现象,现代训诂学显得并不成熟,并且在守旧与改造的矛盾运动中,训诂学往往面临二难处境:如果守旧,那么训诂学势必式微而最后走向终结;如果改造,那么训诂学可能脱胎换骨而最后走向终结.训诂学在加强自身改造的同时,如果注意吸收现代词汇学、语义学以及相关学科的成果,着力加强理论建设和应用性研究,形成百家争鸣、新体系迭出的局面,那么训诂学不仅完全可以走出它目前所面临着的二难处境,并且完全可以走向成熟与繁荣.  相似文献   
993.
中国在崛起的过程中,能源安全日益突出。为了积极应对,中国开始关注与能源相关的地缘政治因素的变动,在双边乃至多边关系中突出以能源合作为特色的“能源外交”。虽然中国在开展能源外交时有其潜在优势,但也面临着挑战。因此,我们应该按照“一个中心、两个基本点”,即以重塑形象为中心,以对能源地缘政治和相互依赖的认知与实践为两个基本点来构建中国能源外交战略。  相似文献   
994.
In this article, we present strategies to help combat the U.S. nursing shortage. Key considerations include providing an attractive work schedule and work environment—critical issues for retaining existing nurses and attracting new nurses to the profession—while at the same time using the set of available nurses as effectively as possible. Based on these ideas, we develop a model that takes advantage of coordinated decision making when managing a flexible workforce. The model coordinates scheduling, schedule adjustment, and agency nurse decisions across various nurse labor pools, each of differing flexibility levels, capabilities, and costs, allowing a much more desirable schedule to be constructed. Our primary findings regarding coordinated decision making and how it can be used to help address the nursing shortage include (i) labor costs can be reduced substantially because, without coordination, labor costs on average are 16.3% higher based on an actual hospital setting, leading to the availability of additional funds for retaining and attracting nurses, (ii) simultaneous to this reduction in costs, more attractive schedules can be provided to the nurses in terms of less overtime and fewer undesirable shifts, and (iii) the use of agency nurses can help avoid overtime for permanent staff with only a 0.7% increase in staffing costs. In addition, we estimate the cost of the shortage for a typical U.S. hospital from a labor cost perspective and show how that cost can be reduced when managers coordinate.  相似文献   
995.
In order to develop a dose‐response model for SARS coronavirus (SARS‐CoV), the pooled data sets for infection of transgenic mice susceptible to SARS‐CoV and infection of mice with murine hepatitis virus strain 1, which may be a clinically relevant model of SARS, were fit to beta‐Poisson and exponential models with the maximum likelihood method. The exponential model (k= 4.1 × l02) could describe the dose‐response relationship of the pooled data sets. The beta‐Poisson model did not provide a statistically significant improvement in fit. With the exponential model, the infectivity of SARS‐CoV was calculated and compared with those of other coronaviruses. The does of SARS‐CoV corresponding to 10% and 50% responses (illness) were estimated at 43 and 280 PFU, respectively. Its estimated infectivity was comparable to that of HCoV‐229E, known as an agent of human common cold, and also similar to those of some animal coronaviruses belonging to the same genetic group. Moreover, the exponential model was applied to the analysis of the epidemiological data of SARS outbreak that occurred at an apartment complex in Hong Kong in 2003. The estimated dose of SARS‐CoV for apartment residents during the outbreak, which was back‐calculated from the reported number of cases, ranged from 16 to 160 PFU/person, depending on the floor. The exponential model developed here is the sole dose‐response model for SARS‐CoV at the present and would enable us to understand the possibility for reemergence of SARS.  相似文献   
996.
The potential for cannibalization of new product sales by remanufactured versions of the same product is a central issue in the continuing development of closed‐loop supply chains. Practitioners have no fact‐based information to guide practice at firms and academics have no studies available to use as the basis for assumptions in models. We address the cannibalization issue by using auctions to determine consumers’ willingness to pay (WTP) for both new and remanufactured products. The auctions also allow us to better understand the potential impact of offering new and remanufactured products at the same time, which provides us insights into the potential for new product cannibalization. Our results indicate that, for the consumer and commercial products auctioned, there is a clear difference in WTP) for new and remanufactured goods. For the consumer product, there is scant overlap in bidders between the new and remanufactured products, leading us to conclude that the risk of cannibalization in this case is minimal. For the commercial product, there is evidence of overlap in bidding behavior, exposing the potential for cannibalization.  相似文献   
997.
We study optimal taxation when consumers have temptation and self‐control problems. Embedding the class of preferences developed by Gul and Pesendorfer into a standard macroeconomic setting, we first prove, in a two‐period model, that the optimal policy is to subsidize savings when consumers are tempted by “excessive” impatience. The savings subsidy improves welfare because it makes succumbing to temptation less attractive. We then study an economy with a long but finite horizon which nests, as a special case, the Phelps–Pollak–Laibson multiple‐selves model (thereby providing guidance on how to evaluate welfare in this model). We prove that when period utility is logarithmic, the optimal savings subsidies increase over time for any finite horizon. Moreover, as the horizon grows large, the optimal policy prescribes a constant subsidy, in contrast to the well known Chamley–Judd result.  相似文献   
998.
We study the impact of product recovery on a firm's product quality choice, where quality is defined as an observable performance measure that increases a consumer's valuation for the product. We consider three general forms of product recovery: (i) when product recovery reuses (after reprocessing) quality inducing components or material (e.g., remanufacturing), (ii) when product recovery does not reuse quality inducing components or material but it is overall profitable (e.g., cell phone recycling), and (iii) when product recovery is costly (but mandated by legislation, e.g., recycling of small appliances in the European Union). Using a stylized economic model, we show that the form of product recovery, recovery cost structure, and the presence of product take‐back legislation play an important role in quality choice. Generally speaking, product recovery increases the firm's quality choice, except for some instances of recovery form (ii). In addition, we find that product take‐back legislation can lead to higher quality choice as opposed to voluntary take‐back. We further demonstrate that both the firm and the consumers benefit from recovery form (ii), while both are worse off with recovery form (iii). However, environmental implications of the three recovery modes differ from their impact on consumer surplus and firm profit. While recovery forms (i) and (iii) reduce consumption and increase environmental benefits, the same is not true with recovery form (ii), which can increase consumption, potentially resulting in higher environmental impact.  相似文献   
999.
We consider the estimation of dynamic panel data models in the presence of incidental parameters in both dimensions: individual fixed‐effects and time fixed‐effects, as well as incidental parameters in the variances. We adopt the factor analytical approach by estimating the sample variance of individual effects rather than the effects themselves. In the presence of cross‐sectional heteroskedasticity, the factor method estimates the average of the cross‐sectional variances instead of the individual variances. The method thereby eliminates the incidental‐parameter problem in the means and in the variances over the cross‐sectional dimension. We further show that estimating the time effects and heteroskedasticities in the time dimension does not lead to the incidental‐parameter bias even when T and N are comparable. Moreover, efficient and robust estimation is obtained by jointly estimating heteroskedasticities.  相似文献   
1000.
We propose a bubble game that involves sequential trading of an asset commonly known to be valueless. Because no trader is ever sure to be last in the market sequence, the game allows for a bubble at the Nash equilibrium when there is no cap on the maximum price. We run experiments both with and without a price cap. Structural estimation of behavioral game theory models suggests that quantal responses and analogy‐based expectations are important drivers of speculation.  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