全文获取类型
收费全文 | 20126篇 |
免费 | 1079篇 |
国内免费 | 385篇 |
专业分类
财政金融 | 2045篇 |
工业经济 | 977篇 |
计划管理 | 4467篇 |
经济学 | 4125篇 |
综合类 | 2159篇 |
运输经济 | 310篇 |
旅游经济 | 467篇 |
贸易经济 | 2639篇 |
农业经济 | 1978篇 |
经济概况 | 2423篇 |
出版年
2024年 | 56篇 |
2023年 | 456篇 |
2022年 | 458篇 |
2021年 | 688篇 |
2020年 | 861篇 |
2019年 | 644篇 |
2018年 | 571篇 |
2017年 | 788篇 |
2016年 | 748篇 |
2015年 | 698篇 |
2014年 | 1447篇 |
2013年 | 1790篇 |
2012年 | 1638篇 |
2011年 | 1847篇 |
2010年 | 1353篇 |
2009年 | 1266篇 |
2008年 | 1354篇 |
2007年 | 1215篇 |
2006年 | 1016篇 |
2005年 | 799篇 |
2004年 | 522篇 |
2003年 | 348篇 |
2002年 | 217篇 |
2001年 | 181篇 |
2000年 | 145篇 |
1999年 | 95篇 |
1998年 | 79篇 |
1997年 | 55篇 |
1996年 | 51篇 |
1995年 | 36篇 |
1994年 | 37篇 |
1993年 | 20篇 |
1992年 | 33篇 |
1991年 | 16篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 10篇 |
1985年 | 14篇 |
1984年 | 11篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Ellis J. Neufeld Robert F. Sidonio Jr M. Chris Runken Kellie Meyer Jeffrey Spears 《Journal of medical economics》2018,21(8):762-769
Background: Inhibitor development to factor VIII (FVIII) hemophilia therapy results in increased complications and substantial economic costs. The SIPPET study, the first randomized controlled trial to compare the immunogenicity of plasma-derived FVIII (pdFVIII)/von Willebrand factor (VWF) and recombinant-DNA-derived FVIII (rFVIII), demonstrated higher inhibitor rates in previously untreated patients (PUPs) treated with rFVIII than in PUPs treated with pdFVIII/VWF.Objective: To quantify the economic impact of treating PUPs with pdFVIII/VWF vs rFVIII.Methods: An Excel-based clinical and economic model was developed from a US healthcare payer perspective and run over a 5-year period. The analysis utilized a cohort approach to model patient treatment and outcomes over a monthly cycle to quantify differences in costs of FVIII, bypassing agents, and hospitalizations for serious bleeds. Rates of high-titer inhibitor development were obtained from the SIPPET study. Patients developing high-titer inhibitors were treated with immune tolerance induction (ITI). Patients who developed low-titer inhibitors and those who did not develop inhibitors continued their usual FVIII treatment. Patients who were successfully treated with ITI returned to FVIII treatment, while unsuccessfully treated patients received bypassing agents. Total costs per treated patient were estimated and a one-way sensitivity analysis was conducted to quantify the impact of parameter uncertainty on the model outcomes.Results: Total cumulative costs per patient over 5 years were $834,621 for pdFVIII/VWF patients and $1,237,163 for rFVIII patients, representing a total saving of $402,542 per patient over the 5-year period, for an average annual saving of $80,508 per patient.Conclusions: Based on data from the SIPPET study, this analysis found that initiating FVIII treatment in severe hemophilia A PUPs with pdFVIII/VWF has the potential to offer substantial cost savings to healthcare payers, amounting to a one-third reduction in costs. 相似文献
102.
提出了一种由单形规范线性分段(SCPWL)函数与记忆多项式级联的数字预失真器,并给出了复数域两步最小二乘参数辨识算法。不同于以往一种预失真器适用一种功放模型的情况,所提的预失真算法利用SCPWL函数的分段特性以及记忆多项式的非线性记忆特性,在完成参数辨识的同时自动地调整结构,可适用于传统以及强非线性新型功放模型的线性化补偿。将所提预失真器分别应用于传统记忆多项式、两箱模型以及新型包络跟踪功放。经过计算机仿真,功放输出的幅频特性和频谱曲线表明所提预失真器能够有效地补偿多种功放的非线性特性。算法仿真比较结果也表明,针对包络跟踪功放,所提复数两步最小二乘算法的邻道泄漏比(ACLR)可改善约35 dB,性能优于最小均方(LMS)类算法约30 dB。 相似文献
103.
This paper presents a theoretical model based on the Technology Acceptance Model combined with a perceived trust model. SPSS 23 and Amos 22 were used to analyze Chinese tourists’ responses regarding use of biometric technology in hotels and to assess whether their perception of trust – measured through five potential factors – affected their intention to use it. Chinese tourists traveling in Macau were recruited, and three types of biological identification technology were discussed. A total of 600 questionnaires were sent out, and 583 effective questionnaires were recovered. The results that in addition to perceived ease of use, other factors affected visitors’ perceptions of trust. The degrees of effectiveness, however, differed between the three biological identification technologies. Fingerprint technology was revealed to be the most trusted and accepted biometric technology. 相似文献
104.
Zhiyuan Wang 《New Political Economy》2018,23(6):656-673
Extant scholarship treats national policies concerning labour rights as a function of economic factors and yet neglects influences of policies among economically competing states. Relying on the policy interdependence theory, this study argues that labour rights policy in a state is dependent on its economic competitors’ labour policy decisions. It specifically maintains that the intensifying competition for foreign direct investment and exports as well as against imports channels negative externalities of deteriorating labour protection in competing states which drives expansive downward policy mimicking and leads to a global decline in labour rights – a race to the bottom. Utilising spatial econometric technique to analyse a new data on labour rights for the period 1994–2009, it finds that labour rights practices are interdependent among economic competitors and experience global deteriorations; whereas labour rights laws remain largely independent due to high policy and reputational costs of lowering them and show more fluctuations. 相似文献
105.
106.
Ignacio Oliva Patricia Galilea Ricardo Hurtubia 《International Journal of Sustainable Transportation》2018,12(10):701-713
Understanding how spatial attributes of cities and neighborhoods induce cycling is relevant for urban planning and policy making. In this work, ordered logit and latent class models are specified and estimated to analyze how the built environment affects bicycle-commuting frequency. Data come from a survey to 1,487 people in the city of Santiago, Chile, including sociodemographic information, travel behavior patterns and place of residence and work. Using geographic information systems tools, the built environment was characterized with variables calculated for a 500-m-radius buffer around the residential and work locations of each individual. Two models are estimated, first an ordered logit model confirms that built environment variables effect on cycling is similar to what has been reported in the literature, with some new findings such as an increase in cycling when public transport accessibility is low and the role of built environment attributes at the destination. Second, a latent class ordered logit is used to identify two classes of neighborhood in term of their cycling patterns, as a function of their density, presence of cycling infrastructure and distance to the main activity center of the city. This result allows to map the class membership probabilities, potentially helping to identify neighborhoods that encourage cycling and providing relevant information for policy making and infrastructure decisions. 相似文献
107.
Allan F. Pinto Brittney K. Goodrich William Kelley Max Runge 《Revue canadienne d'agroeconomie》2023,71(1):5-23
Replacement brood cows are among the most significant investments for cow-calf operations, thus crucial to profitability. Many cow-calf producers find it cost effective to purchase replacements from a reliable replacement heifer seller, though by doing so they increase risk of reproductive inefficiency due to unknown characteristics of the heifers. When important information about a product is missing to buyers, a seller can build a reputation over time that acts as signal for quality. Previous work has explored reputation effects in feeder cattle markets, but to our knowledge we are the first to explore reputation effects in bred replacement cattle markets. Using data from an annual replacement heifer sale, we analyze the values of heifer characteristics and test for premiums from reputation development. After controlling for reproductive practices, breed, and other characteristics, we find reputation does not play the role that Shapiro theorized. In this sale, the lot order is strategically chosen and may indicate bred heifer quality to buyers, replacing the need for reputation as a signal. This study highlights the importance of quality signals and regional preferences in bred replacement cattle marketing and lays the empirical groundwork for future studies to test Shapiro's theory. 相似文献
108.
A demand function of online shopping supply chain based on online-to-offline (O2O) fusion degree is proposed by considering the low-carbon awareness of online shoppers in view of the low-carbon decision making of supply chain in combination with the O2O operation background. On this basis, a low-carbon decision-making model based on online stores and their suppliers is established, and the application of the model is analyzed. Results show that the promotion of low-carbon operation is efficient when the consistency of online and offline operations of online stores and their suppliers is high. In addition, the decision making considering the cost of carbon information release is highly conducive to improving the low-carbon awareness of online shoppers if the low-carbon level of online shopping goods is lower than the low-carbon standard. Accordingly, the low-carbon operation of online shopping supply chain will be promoted. 相似文献
109.
随着互联网的快速发展,我国的手机愈发成为一部掌上电脑,通过手机进行外卖订餐已经成为现代高校大学生的日常状态,外卖的物流配送大大改变了学生的生活饮食方式。但是高校周围的外卖物流配送也容易导致很多问题,影响大学生的生活。针对高校外卖的特殊性,文章以互联网下逐渐形成的O2O模式来研究高校外卖物流配送的现状与发展,并且针对存在的问题提出相关建议。 相似文献
110.
《International Journal of Forecasting》2021,37(4):1399-1425
Dynamic factor models have been the main “big data” tool used by empirical macroeconomists during the last 30 years. In this context, Kalman filter and smoothing (KFS) procedures can cope with missing data, mixed frequency data, time-varying parameters, non-linearities, non-stationarity, and many other characteristics often observed in real systems of economic variables. The main contribution of this paper is to provide a comprehensive updated summary of the literature on latent common factors extracted using KFS procedures in the context of dynamic factor models, pointing out their potential limitations. Signal extraction and parameter estimation issues are separately analyzed. Identification issues are also tackled in both stationary and non-stationary models. Finally, empirical applications are surveyed in both cases. This survey is relevant to researchers and practitioners interested not only in the theory of KFS procedures for factor extraction in dynamic factor models but also in their empirical application in macroeconomics and finance. 相似文献