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   19488篇
  免费   577篇
  国内免费   12篇
财政金融   3154篇
工业经济   1433篇
计划管理   2966篇
经济学   3657篇
综合类   281篇
运输经济   129篇
旅游经济   275篇
贸易经济   2450篇
农业经济   817篇
经济概况   2416篇
水利工程   2485篇
信息产业经济   1篇
邮电经济   13篇
  2023年   95篇
  2021年   192篇
  2020年   256篇
  2019年   286篇
  2018年   419篇
  2017年   426篇
  2016年   404篇
  2015年   290篇
  2014年   450篇
  2013年   1803篇
  2012年   779篇
  2011年   855篇
  2010年   735篇
  2009年   748篇
  2008年   748篇
  2007年   710篇
  2006年   747篇
  2005年   624篇
  2004年   538篇
  2003年   371篇
  2002年   331篇
  2001年   348篇
  2000年   365篇
  1999年   331篇
  1998年   290篇
  1997年   293篇
  1996年   280篇
  1995年   246篇
  1994年   250篇
  1993年   284篇
  1992年   256篇
  1991年   263篇
  1990年   241篇
  1989年   231篇
  1988年   217篇
  1987年   199篇
  1986年   216篇
  1985年   299篇
  1984年   279篇
  1983年   274篇
  1982年   242篇
  1981年   232篇
  1980年   247篇
  1979年   202篇
  1978年   175篇
  1977年   165篇
  1976年   150篇
  1975年   131篇
  1974年   112篇
  1973年   111篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
The main objective of this paper it to model the dynamic relationship between global averaged measures of Total Radiative Forcing (RTF) and surface temperature, measured by the Global Temperature Anomaly (GTA), and then use this model to forecast the GTA. The analysis utilizes the Data-Based Mechanistic (DBM) approach to the modelling and forecasting where, in this application, the unobserved component model includes a novel hybrid Box-Jenkins stochastic model in which the relationship between RTF and GTA is based on a continuous time transfer function (differential equation) model. This model then provides the basis for short term, inter-annual to decadal, forecasting of the GTA, using a transfer function form of the Kalman Filter, which produces a good prediction of the ‘pause’ or ‘levelling’ in the temperature rise over the period 2000 to 2011. This derives in part from the effects of a quasi-periodic component that is modelled and forecast by a Dynamic Harmonic Regression (DHR) relationship and is shown to be correlated with the Atlantic Multidecadal Oscillation (AMO) index.  相似文献   
3.
We extend the entrepreneurship literature to include positive psychological capital — an individual or organization's level of psychological resources consisting of hope, optimism, resilience, and confidence — as a salient signal in crowdfunding. We draw from the costless signaling literature to argue that positive psychological capital language usage enhances crowdfunding performance. We examine 1726 crowdfunding campaigns from Kickstarter, finding that entrepreneurs conveying positive psychological capital experience superior fundraising performance. Human capital moderates this relationship while social capital does not, suggesting that costly signals may, at times, enhance the influence of costless signals. Post hoc analyses suggest findings generalize across crowdfunding types, but not to IPOs.  相似文献   
4.
Abstract

Traditional warranty analysis focuses on the reliability of a product and offers warranty designs that compensate a consumer if the item fails. We introduce the concept of a performance-based warranty (PBW) that guarantees that a product will operate at or above some baseline level of performance, such as a minimum energy efficiency for an appliance. We illustrate how consumer behavior can change in the presence of a PBW and define the parameters for which a manufacturer may increase revenue. Finally, we present an algorithm to solve for the optimal PBW design given a consumer’s belief about the expected performance of the product.  相似文献   
5.
科技服务业产出测算是对科技服务业产出数据的统计与分析,加强科技服务业产出数据的规范统计和应用分析可为我国政府调整产业政策提供重要数据支撑。以科技服务业产出测算为研究对象,结合学者观点、国家标准及各级政府相关产业政策,提出将分支产业作为初始指标的横向统计思路,构建科技服务业产出测算指标体系。在数据收集方面,强调要做好“收”与“填”两个基本工作;在指标确立和数据收集基础上,进一步提出未来预测的两种方法,以此作为科技服务业产出数据预测的初步探索;提出应从统一数据统计标准、完善数据调查与公开制度、加强数据资源开发3个方面建立健全我国科技服务业产出数据测量与管理体制机制。  相似文献   
6.
The emergence of the COVID-19 pandemic has adversely affected the fortunes of multiple companies around the globe. Accordingly, questions are increasingly being asked about how organizations can revitalize during and after a crisis. Yet, we have limited understanding of how organizations renew themselves during crises over time. We explore this question through the lens and examination of two South-Asian airlines: Pakistan International Airlines and Sri Lankan Airlines. The cases offer important insights into the reasons behind underperformance of state-controlled enterprises and renewal activities. We shed light on strategic renewal (SR) in the wake of increasing liberalization and deregulations in the global airline industry. To this end, we propose a four-stage approach towards renewing such underperforming organizations to respond effectively to black swan events and external shocks.  相似文献   
7.
Quantitative Marketing and Economics - Little is known about how different types of advertising affect brand attitudes. We investigate the relationships between three brand attitude variables...  相似文献   
8.
An economic recession is a type of crisis originated from external factors that may imperil an organization’s survival depending on the intensity and duration of the crisis. In peripheral European countries, such as Portugal, the recent financial crisis had devastating effects on various business activities. As a result, Portugal represents an important case study in examining how some corporate leaders have handled the economic recession successfully. I interviewed 20 corporate managers to capture their perceptions of the leadership traits and behaviors exhibited by their CEOs in guiding their companies through the recession. In economic recessions, negative constraints do not affect the most effective leaders, who instead erect barriers against the high-pressure conditions to create a supportive, positive work environment. In order to achieve maximum effectiveness, leaders must act as blocking agents against the negative social impacts of the economic crisis, including the fragility of trust in organizational life (i.e., a barrier against distrust), uncertainty of the future (i.e., a barrier against uncertainty), and toxic emotions (i.e., a barrier against toxic emotions).  相似文献   
9.
This article measures the size and incomes of six major social classes across the industrial revolution using social tables for England and Wales in 1688, 1759, 1798, 1846, and 1867. Lindert and Williamson famously revised these tables, and this article extends their work in three directions. First, servants are removed from middle‐ and upper‐class households in the tables of King, Massie, and Colquhoun and tallied separately. Second, estimates are made for the same tables of the number and incomes of women and children employed in the various occupations, and, third, incomes are broken down into rents, profits, and employment income. These extensions to the tables allow variables to be computed that can be checked against independent estimates as a validation exercise. The tables are retabulated in a standardized set of six social groups to highlight the changing structure of society across the industrial revolution. Gini coefficients are computed from the social tables to measure inequality. These measures confirm that Britain traversed a ‘Kuznets curve’ in this period. Changes in overall inequality are related to the changing fortunes of the major social classes.  相似文献   
10.
Wastewater treatment plant operators encounter complex operational problems related to the activated sludge process and usually respond to these by applying their own intuition and by taking advantage of what they have learnt from past experiences of similar problems. However, previous process experiences are not easy to integrate in numerical control, and new tools must be developed to enable re-use of plant operating experience. The aim of this paper is to investigate the usefulness of a case-based reasoning (CBR) approach to apply learning and re-use of knowledge gained during past incidents to confront actual complex problems through the IWA/COST Benchmark protocol. A case study shows that the proposed CBR system achieves a significant improvement of the benchmark plant performance when facing a high-flow event disturbance.  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