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   768篇
  免费   2篇
财政金融   150篇
工业经济   36篇
计划管理   147篇
经济学   200篇
运输经济   13篇
旅游经济   14篇
贸易经济   144篇
农业经济   25篇
经济概况   39篇
邮电经济   2篇
  2024年   6篇
  2023年   8篇
  2022年   2篇
  2021年   10篇
  2020年   28篇
  2019年   45篇
  2018年   25篇
  2017年   33篇
  2016年   43篇
  2015年   22篇
  2014年   37篇
  2013年   119篇
  2012年   44篇
  2011年   48篇
  2010年   32篇
  2009年   26篇
  2008年   39篇
  2007年   25篇
  2006年   23篇
  2005年   14篇
  2004年   15篇
  2003年   23篇
  2002年   23篇
  2001年   13篇
  2000年   7篇
  1999年   9篇
  1998年   6篇
  1997年   8篇
  1996年   4篇
  1995年   1篇
  1994年   2篇
  1993年   3篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1984年   2篇
  1983年   1篇
  1982年   3篇
  1981年   1篇
  1980年   2篇
  1978年   1篇
  1977年   3篇
  1976年   1篇
  1968年   1篇
  1959年   1篇
  1939年   2篇
排序方式: 共有770条查询结果,搜索用时 15 毫秒
141.
142.
Along with the oil price, concerns about the security of energy supply have soared once again in recent years. In this paper, we analyze Germany’s past und future energy security situation and compare it to that of other G7 countries using a statistical indicator of the long-term energy supply risk and empirical energy data for the years 1978 through 2007. We find that Germany’s energy supply risk has increased substantially since the oil price crises of the 1970s, whereas France and Japan have managed to reduce their risks dramatically, most notably through the deployment of nuclear power plants. Among G7 countries, Germany’s risk is only surpassed by that of Italy, while it can be expected that the German energy security situation may deteriorate in the future, not least due to the phase-out of nuclear power.  相似文献   
143.
Background: A five-year retrospective database analysis comparing the use of Floseal1 flowable topical hemostat alone (F) and in combination with gelatin/thrombin (F?+?G/T) to achieve hemostasis and control surgical bleeding showed higher resource utilization for F?+?G/T cases relative to F matched pairs during spinal surgery. Lower resource use in the F group was characterized by shorter hospital length of stay and surgical time as well as fewer blood transfusions and less hemostat agent used per surgery.

Objective: To evaluate the cost–consequence of using F compared to F?+?G/T in minor, major and severe spinal surgery from the US hospital perspective.

Methods: A cost–consequence model was developed using the US hospital perspective. Model inputs include clinical inputs from the literature, cost inputs (hemostatic matrices, blood product transfusion, hospital stay and operating room time) from the literature, and an analysis of annual spine surgery volume (minor, major and severe) using the 2012 National Inpatient Sample (NIS) database. Costs are reported in 2017?US dollars. One-way and probabilistic sensitivity analyses address sources of variability in the results.

Results: A medium-volume hospital (130 spine surgeries per year) using F versus F?+?G/T for spine surgeries is expected to require 85 less hours of surgical time, 58 fewer hospital days and 7 fewer blood transfusions in addition to hemostat volume savings (F: 1?mL, thrombin: 1994?mL). The cost savings associated with the hospital resources for a medium-volume hospital are expected to be $317,959 (surgical hours?=?$154,746, hospital days?=?$125,237, blood transfusions?=?$19,023, hemostatic agents?=?$18,953) or $2445 per spine surgery.

Conclusions: The use of F versus F?+?G/T could lead to annual cost savings for US hospitals performing a low to high volume of spinal surgeries per year.  相似文献   
144.
145.
146.
    
The purpose of this article is to propose a novel classification of the interrelationships between Industry 4.0 (I4.0) technologies and circular economy (CE) principles that highlights the most conclusive findings and extant gaps in the relevant research. A systematic literature review has been developed to locate, select and evaluate relevant contributions made to CE interrelationships with I4.0 technologies. Studies have been analysed and classified according to the specific I4.0 technology and CE principle addressed (10Rs). The articles have been clustered into three main groups: (i) useful application of materials, (ii) extending the lifespan of products and their parts and (iii) smarter product use and manufacture. A mind map of the investigated articles has been used to establish the interrelationships between individual technologies and each CE principle at the supply chain level. Based on this classification, a focus group interview (FGI) was held with experts to dig deeper into the interrelationships between I4.0 technologies and CE principles. The FGI results have identified how each as yet unexplored I4.0 technology could be linked to each CE principle. A Fuzzy Delphi (FD) study was also applied to identify the most relevant I4.0 technologies for improving CE principles and closing gaps in the literature regarding the 10R CE principles. In addition, guidelines have been established to assist with practical applications and generate a research agenda on the interrelationships between I4.0 technologies and CE principles at the supply chain level. Implications for theory include the extension of view from the research gaps between I4.0 technologies and the 10Rs identified in the literature; also, an FGI and FD were performed based on the detected research gaps to identify future lines of research for academics and offer useful guidance to directors and managers on I4.0 technology interrelationships for improving at least one of the 10R CE principles. The contribution to practice aims to enable managers to easily identify which technology from the I4.0 domain should be used to advance any given CE principle. Lastly, we provide useful guidance on the application of as-yet-unused technologies to improve CE principles.  相似文献   
147.
Increasing electric power production from renewable energy sources is currently one of the major objectives of energy policy. The intermittent nature of renewables, such as wind and solar, necessarily imposes complex trade-offs for regulatory objectives, such as resource adequacy (and system reliability) versus reductions in green house gas emissions. We develop a highly stylized model of investments in order to derive insights regarding the workings of regulatory incentives for increased renewable energy. We first show that incentives are indeed needed when there are significant economies of scale in the form of “learning by doing” or alternatively, when there is excess capacity in conventional technology due to legacy investments. We analyze two different regulatory schemes (feed-in tariffs and renewable portafolio standards) aimed at increasing investment in renewable capacity. We show that neither scheme is capable of inducing the socially optimal level of investment in renewable capacity. A single feed-in tariff fails to induce optimal investment as a feed-in tariff exceeding marginal costs of conventional technology incentivizes over-development of the most attractive sites which preempts investment in less attractive, yet socially valuable sites. A renewable portfolio standard that promotes increased investment in renewable technology induces under-investment in the conventional technology. These results suggest that a “clinical” regulatory design, that is, one that promotes the right amount of renewable capacity without affecting conventional capacity is a challenging proposition.  相似文献   
148.
    
The aim of this paper is to assess the efficiency of football. Our contributions to the literature are the use of the resource-based theory and the strategy-structure-performance perspective as the study's framework, efficiency has been considered as the result of the qualities of the productive resources in football teams and efficiency is calculated in every area in the field of play. The results show that the entire team's efficiency is positively related to sporting success and the efficiency of attacking and ball recovery areas is directly related to the sport result and the efficiency of the team as a whole.  相似文献   
149.
150.
We focus on how interpersonal characteristics should influence leader support for gender equity in organizations. Recognizing gender disparities in organizations and the “labyrinth” that women face when they advance in their careers (cf. Eagly & Carli, 2007), we develop a model for how interpersonal characteristics of leaders, both men and women, influence power construal and thus their use of empowerment, mentoring, and performance feedback, ultimately affecting career opportunities for women in organizations. The model proposes that leaders who are high on communal goal orientation, a prosocial characteristic, are more likely to construe power through a responsibility lens and behave in ways that ultimately support gender equity in organizations. In contrast, leaders with an exchange goal orientation are more likely to construe power through a freedom lens and behave in ways that are self-serving. Prestige motivation will increase the extent to which leaders, especially those who are communally oriented, share power. Dominance motivation will increase the extent to which leaders, especially those who are exchange oriented, act in self-interest and retain power, ultimately imposing barriers to women's career advancement. Organizations can potentially increase leader power sharing by encouraging and reinforcing leaders' prosocial characteristics of communal orientation and prestige motivation. Implications for research and practice are discussed.  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