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   6730篇
  免费   449篇
财政金融   926篇
工业经济   307篇
计划管理   1332篇
经济学   1988篇
综合类   46篇
运输经济   148篇
旅游经济   146篇
贸易经济   1585篇
农业经济   238篇
经济概况   454篇
邮电经济   9篇
  2024年   6篇
  2023年   134篇
  2022年   96篇
  2021年   131篇
  2020年   244篇
  2019年   285篇
  2018年   429篇
  2017年   549篇
  2016年   463篇
  2015年   257篇
  2014年   321篇
  2013年   1251篇
  2012年   352篇
  2011年   314篇
  2010年   343篇
  2009年   291篇
  2008年   248篇
  2007年   192篇
  2006年   174篇
  2005年   159篇
  2004年   115篇
  2003年   110篇
  2002年   93篇
  2001年   74篇
  2000年   58篇
  1999年   55篇
  1998年   46篇
  1997年   34篇
  1996年   24篇
  1995年   22篇
  1994年   21篇
  1993年   16篇
  1992年   16篇
  1991年   16篇
  1990年   10篇
  1989年   16篇
  1988年   6篇
  1987年   5篇
  1986年   6篇
  1985年   18篇
  1984年   23篇
  1983年   15篇
  1982年   17篇
  1981年   14篇
  1980年   6篇
  1979年   6篇
  1977年   5篇
  1976年   7篇
  1974年   9篇
  1889年   4篇
排序方式: 共有7179条查询结果,搜索用时 890 毫秒
971.
This study aimed to describe the distribution of injury mechanisms and to assess the impact of those mechanisms on the morbidity and mortality of trauma. All patients admitted to Puerto Rico Trauma Hospital (2002–2011) for road-traffic collisions (RTCs, 5,371), gunshot wounds (GSWs, 2,946), falls (2,319), pedestrian accidents (1,652), and stab wounds (SWs, 1,073) were selected. Gunshot victims were 1.19 (95%CI: 1.07–1.33) times as likely as road-traffic victims to have an ISS ≥25. Pedestrians were 1.76 (95%CI: 1.49–2.09) times more likely to have a GCS ≤8 than road-traffic victims were. The risk of dying was 2.64 (95%CI: 2.20–3.16) times higher for gunshot victims and 1.51 (95%CI: 1.23–1.86) times higher for pedestrians compared to patients who had had RTCs. Gunshot victims and pedestrians had the worst clinical outcomes. Accordingly, these patients should receive the most aggressive clinical management. Furthermore, it is imperative to develop public health campaigns on trauma prevention.  相似文献   
972.
973.
In the last three decades, a variety of stochastic reserving models have been proposed in the general insurance literature mainly using (or reproducing) the well-known Chain-Ladder claims-reserving estimates. In practice, when the data do not satisfy the Chain-Ladder assumptions, high prediction errors might occur. Thus, in this article, a combined methodology is proposed based on the stochastic vector projection method and uses the regression through the origin approach of Murphy, but with heteroscedastic errors instead, and different from those that used by Mack. Furthermore, the Mack distribution-free model appears to have higher prediction errors when compared with the proposed one, particularly, for data sets with increasing (regular) trends. Finally, three empirical examples with irregular and regular data sets illustrate the theoretical findings, and the concepts of best estimate and risk margin are reported.  相似文献   
974.
Two-part models based on generalized linear models are widely used in insurance rate-making for predicting the expected loss. This paper explores an alternative method based on quantile regression which provides more information about the loss distribution and can be also used for insurance underwriting. Quantile regression allows estimating the aggregate claim cost quantiles of a policy given a number of covariates. To do so, a first stage is required, which involves fitting a logistic regression to estimate, for every policy, the probability of submitting at least one claim. The proposed methodology is illustrated using a portfolio of car insurance policies. This application shows that the results of the quantile regression are highly dependent on the claim probability estimates. The paper also examines an application of quantile regression to premium safety loading calculation, the so-called Quantile Premium Principle (QPP). We propose a premium calculation based on quantile regression which inherits the good properties of the quantiles. Using the same insurance portfolio data-set, we find that the QPP captures the riskiness of the policies better than the expected value premium principle.  相似文献   
975.
The circular economy emerged as an alternative model to the linear system, which now appears to be reaching its physical limitations. To transition to a circular economy, companies must not only be aware of but also engage in more sustainable practices. For such a transition, companies must rethink and innovate their business models and the ways they propose value to their clients while simultaneously considering environmental and social facets. This systematic literature review sought to map out from the company perspective the key topics interrelated with innovation and the circular economy, describing the internal and external factors to consider in such transition processes. Key lines of research were identified, and suggestions for future research and for facilitating movement toward a circular economy are provided. This work contributes to deepening the literature by identifying the priority areas concerning the circular economy and encouraging future research that meets international standards of excellence.  相似文献   
976.
Open Economies Review - This paper aims at building a money demand function that takes account of the heterogeneities of the Central and Eastern European Countries (CEECs) in the context of the...  相似文献   
977.
This study analyzes the effect of informational clues and Chef-Cuisine congruence, and their relation to advertisements for a Japanese restaurant. Two experiments were conducted with 171 consumers. Findings supported the following: Congruence between a Japanese restaurant and Japanese Chef results in higher approval ratings than the combination of Japanese restaurant with Brazilian Chef. However, if the advertisement states that the restaurant has won an award, then Chef-restaurant congruence is no longer an important factor in consumers’ evaluations.  相似文献   
978.
We model endogenous catastrophic risk in a new way. We call it “inertia risk”, which accounts for delays between physical variables and the hazard rate – a characteristic often observed in reality. The added realism significantly affects optimal policies relative to the standard model of catastrophic risk. The probability of a catastrophe occurring at some point in time can span the entire interval [0,1], and is not 0 or 1 as is typical in standard models. Inertia risk can also generate path dependences. We illustrate the implications for policy in a simple model of climate change.  相似文献   
979.
Mobile devices and social media have led to a profound revolution of modern society, obliging many companies to reorient their sales systems towards more successful commercial formats (mobile commerce and social commerce). The mobile payment, for instance, as an emerging and supplementary service to these new commercial formats, is now undergoing the adoption process. Mobile payment has long been discussed, but it has not yet reached the usage levels expected by the different mass market players (financial institutions, telephone operators, etc.) in Western societies. The purpose of this paper is to analyze users’ acceptance of mobile payment systems on social networks. In order to explain acceptance, we have integrated trust and perceived risk into the traditional TAM model. To complete this study, we have established the decisive factors of this payment system by analyzing user’s gender, age and experience level. The study was conducted through an online survey among a national panel composed by 2.012 social network users. The results of this research support previous studies and provide alternatives for companies to consolidate this new business model by means of the new technical developments.  相似文献   
980.
This paper focuses on a new strand of research that uses stochastic approach for making spatial price comparisons. We propose a novel method to account for the presence of spatial dependencies in consumer prices and consequently in price indexes by imposing penalization conditions on the estimation of traditional CPD models leading to the spatially-penalized country-product-dummy (SP-CPD) model. The paper proposes an appropriate estimation strategy, which enables us to simultaneously estimate all the parameters in the model, including the smoothing parameter of the penalization term instead of determining it externally. In order to estimate spatial price indexes for areas lacking in price data, we suggest applying the kriging methodology to the price indexes obtained from the SP-CPD model. This new approach is applied to official Italian CPI data for constructing regional spatial price indexes for 2014. The results show that price levels are higher in the Northern-Central regions than in the South.  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