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   2846篇
  免费   162篇
财政金融   512篇
工业经济   210篇
计划管理   520篇
经济学   700篇
综合类   30篇
运输经济   40篇
旅游经济   82篇
贸易经济   522篇
农业经济   165篇
经济概况   209篇
信息产业经济   1篇
邮电经济   17篇
  2023年   22篇
  2022年   19篇
  2021年   37篇
  2020年   62篇
  2019年   95篇
  2018年   119篇
  2017年   145篇
  2016年   114篇
  2015年   75篇
  2014年   142篇
  2013年   334篇
  2012年   132篇
  2011年   154篇
  2010年   124篇
  2009年   152篇
  2008年   125篇
  2007年   105篇
  2006年   87篇
  2005年   78篇
  2004年   60篇
  2003年   73篇
  2002年   69篇
  2001年   50篇
  2000年   37篇
  1999年   31篇
  1998年   46篇
  1997年   49篇
  1996年   43篇
  1995年   27篇
  1994年   34篇
  1993年   37篇
  1992年   31篇
  1991年   17篇
  1990年   20篇
  1989年   18篇
  1988年   15篇
  1987年   8篇
  1986年   11篇
  1985年   22篇
  1984年   20篇
  1983年   19篇
  1982年   12篇
  1981年   20篇
  1980年   15篇
  1979年   19篇
  1978年   12篇
  1977年   19篇
  1976年   12篇
  1975年   11篇
  1971年   6篇
排序方式: 共有3008条查询结果,搜索用时 15 毫秒
991.
Objective:

To evaluate the health system costs among patients with hemophilia A and B with and without inhibitors over 5 years.

Methods:

This was a retrospective, observational study utilizing medical and pharmacy electronic medical records and administrative encounters/claims data tracking US patients between 2006–2011. Patients with diagnosis codes for hemophilia A and B were identified. Patients with inhibitors were characterized by utilization of bypassing agents activated prothrombin complex concentrate or factor VIIa on two or more distinct dates. Severity was classified as mild, moderate, or severe based on laboratory tests of clotting factor.

Results:

There were 160 hemophilia A patients and 54 hemophilia B patients identified. From this group, seven were designated as patients with inhibitors (five with hemophilia A and two with hemophilia B). Hemophilia A patients without inhibitors reported 65 (41.9%) as being severe, 19 (12.3%) as moderate, and 71 (45.8%) as mild. Hemophilia B patients without inhibitors reported nine (17.3%) had severe, 13 (25.0%) had moderate, and 30 (57.7%) had mild hemophilia. All patients with inhibitors had been hospitalized in the previous 5 years compared to 64 (41.3%) with hemophilia A without inhibitors and 22 (42.3%) with hemophilia B without inhibitors. The median aggregate cost per year (including factor and health resource use) was $325,780 for patients with inhibitors compared to $98,334 for hemophilia A patients without inhibitors and $23,265 for hemophilia B patients without inhibitors.

Conclusions:

The results suggest that, while the frequency of inhibitors within the hemophilia cohort was low, there was a higher frequency of hospitalizations, and the associated median aggregate costs per year were 3-fold higher than those patients without inhibitors. In contrast, hemophilia B patients experience less severe disease and account for lower aggregate yearly costs compared to either patients with hemophilia A or patients with inhibitors.  相似文献   

992.
The story of Infosys’ growth and transformation from a $250 start-up to its current market valuation of approximately $26 billion provides one of the most pertinent lessons in leveraging India's strengths and managing the challenges faced by an emerging market global enterprise based in India. In this article, we present a wide-ranging interview with Infosys’ current CEO, Mr. S.D. Shibulal, as he explains what he considers to be the core strengths of the company that made it successful in the past, lays out his vision for the company's future, and discusses in detail how he sees the company's transformation taking place over the coming years. The conversation uncovers several interesting themes and lessons for multinational enterprises in emerging as well as developed economies, including the relevance of being born global, values-based governance, the necessity of creating hybrid business models that infuse the ‘India way’ with local cultures and practices in global markets, leveraging strategic partnerships via co-creation and co-evolution, and the delicate balance between ‘preservation-creation-destruction.’  相似文献   
993.
The stock of sovereign debt is typically measured at face value. Defined as the undiscounted sum of future principal repayments, face values are misleading when debts are issued with different contractual forms or maturities. In this paper, we construct alternative measures of the stock of external sovereign debt for 100 developing countries from 1979 through 2006 that correct for differences in contractual form and maturity. We show that our alternative measures: (1) paint a very different quantitative, and in some cases also qualitative, picture of the stock of developing country external sovereign debt; (2) often invert rankings of indebtedness across countries, which historically defined eligibility for debt forgiveness; (3) indicate that the empirical performance of the benchmark quantitative model of sovereign debt deteriorates by roughly 50% once model-consistent measures of debt are used; (4) show how the spread of aggregation clauses in debt contracts that award creditors voting power in proportion to the contractual face value may introduce inefficiencies into the process of restructuring sovereign debts; and (5) illustrate how countries have manipulated their debt issuance to meet fiscal targets written in terms of face values.  相似文献   
994.
This study furthers the research agenda on Porter's generic strategies by exploring their implementation by firms that suffer from under representation in the literature. It focuses on agribusinesses based in emerging markets that specialize in high value added products. Relying on information collected through interviews, and a survey with 66 agribusinesses based in eight countries of Latin America, it examines the factors that distinguish firms implementing a differentiation strategy (DS). The findings provide interesting insights for scholars and practitioners alike, illustrating the strategic initiatives that DS firms use to ensure they command higher than average prices.  相似文献   
995.
This article investigates Russia's historical and current innovation initiatives through the lens of institutional theory, utilizing the triple‐helix innovation model, which we have extended to include the context of Russian culture. The Russian government has embarked upon a national innovation policy and has committed billions of dollars with the goal of developing a knowledge‐based economy to enhance participation in the global arena, while simultaneously diversifying away from energy and natural resources. Historically, Russia has typically not succeeded with innovation beyond the idea, and sometimes product development, stages. Our primary conclusion is that the inadequacy of formal and informal institutional support has created historical barriers in Russia, some of which are currently being addressed to develop an innovation ecosystem encompassing a more supportive institutional infrastructure. The article concludes with implications for US firms and universities involved with innovation activities in Russia. © 2014 Wiley Periodicals, Inc.  相似文献   
996.
Due to the increasing importance of producing and consuming energy more sustainably, Energy Informatics (EI) has evolved into a thriving research area within the CS/IS community. The article attempts to characterize this young and dynamic field of research by describing current EI research topics and methods and provides an outlook of how the field might evolve in the future. It is shown that two general research questions have received the most attention so far and are likely to dominate the EI research agenda in the coming years: How to leverage information and communication technology (ICT) to (1) improve energy efficiency, and (2) to integrate decentralized renewable energy sources into the power grid. Selected EI streams are reviewed, highlighting how the respective research questions are broken down into specific research projects and how EI researchers have made contributions based on their individual academic background.  相似文献   
997.
Agriculture is unique among economic sectors in the nature of impacts from climate change. The production activity that transforms inputs into agricultural outputs involves direct use of weather inputs (temperature, solar radiation available to the plant, and precipitation). Previous studies of the impacts of climate change on agriculture have reported substantial differences in outcomes such as prices, production, and trade arising from differences in model inputs and model specification. This article presents climate change results and underlying determinants from a model comparison exercise with 10 of the leading global economic models that include significant representation of agriculture. By harmonizing key drivers that include climate change effects, differences in model outcomes were reduced. The particular choice of climate change drivers for this comparison activity results in large and negative productivity effects. All models respond with higher prices. Producer behavior differs by model with some emphasizing area response and others yield response. Demand response is least important. The differences reflect both differences in model specification and perspectives on the future. The results from this study highlight the need to more fully compare the deep model parameters, to generate a call for a combination of econometric and validation studies to narrow the degree of uncertainty and variability in these parameters and to move to Monte Carlo type simulations to better map the contours of economic uncertainty.  相似文献   
998.
Overcapacity (OC) and excess capacity (EC) are serious obstacles affecting the sound management of commercial fisheries around the world. The use of individual fishing quotas (IFQs) has been proposed as a promising management tool to cope with these challenges. However, the empirical evidence on the efficacy of this instrument is scarce. Drawing on a stochastic distance frontier analysis, we investigate the impact of the US Gulf of Mexico red snapper IFQ program on fishing capacity, capacity utilisation (CU) and OC. The paper also offers an alternative approach to compute species‐specific capacity measurements for multispecies fisheries. Our findings show that following the introduction of the IFQ program, fishing capacity decreased, primarily due to the exit of a large number of fishing vessels. CU increased marginally indicating modest decreases in EC. Conversely, we find that OC remains high. Our estimates suggest that about one‐fifth of the actual fleet could harvest the entire quota.  相似文献   
999.
We investigate the impacts of multilateral removal of all border taxes and farm programs and their distortions on developing economies, using a world agriculture partial equilibrium model. We quantify changes in prices, trade flows, and production locations. Border measures and farm programs both affect world trade, but trade barriers have the largest impact. Following removal, trade expansion is substantial for most commodities, especially dairy, meats, and vegetable oils. Net agricultural and food exporters emerge with expanded exports; net importing countries with limited distortions before liberalization are penalized by higher world prices and reduced imports. We draw implications for current World Trade Organization negotiations.  相似文献   
1000.
The Contribution of Bioenergy to a New Energy Paradigm   总被引:1,自引:0,他引:1  
Biomass is a widely available resource that is receiving increased consideration as a renewable substitute for fossil fuels. Developed sustainably and used efficiently, it can induce growth in developing countries, reduce oil demand, and address environmental problems. The potential benefits include: reduction of greenhouse gases, recuperation of soil productivity and degraded land, economic benefits from adding value to agricultural activities and improving access to and quality of energy services. The production of bioenergy involves a range of technologies, including solid combustion, gasification, and fermentation. These technologies produce energy from a diverse set of biological resources - traditional crops, crop residues, energy-dedicated crops, dung, and the organic component of urban waste. The results are bioenergy products that provide multiple energy services: cooking fuel, heat, electricity and transportation fuels. It is this very diversity that holds the potential of a win-win-win for the environment, social and economic development. Bioenergy has to be viewed not as a replacement for oil, but as an element of a portfolio of renewable sources of energy. Coherent and mutually supportive environmental and economic policies may be needed to encourage the emergence of a globally dispersed bioenergy industry that will pursue a path of sustainable development.  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