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   134651篇
  免费   3672篇
  国内免费   1篇
财政金融   25362篇
工业经济   11513篇
计划管理   21395篇
经济学   28777篇
综合类   1442篇
运输经济   951篇
旅游经济   2480篇
贸易经济   23329篇
农业经济   6053篇
经济概况   16768篇
信息产业经济   7篇
邮电经济   247篇
  2021年   829篇
  2020年   1611篇
  2019年   2366篇
  2018年   2283篇
  2017年   2460篇
  2016年   2661篇
  2015年   2070篇
  2014年   3377篇
  2013年   15209篇
  2012年   4161篇
  2011年   4080篇
  2010年   3649篇
  2009年   4276篇
  2008年   3839篇
  2007年   3174篇
  2006年   3536篇
  2005年   3531篇
  2004年   3073篇
  2003年   2850篇
  2002年   2827篇
  2001年   2590篇
  2000年   2523篇
  1999年   2418篇
  1998年   2269篇
  1997年   2318篇
  1996年   2190篇
  1995年   1980篇
  1994年   1996篇
  1993年   1970篇
  1992年   2014篇
  1991年   1914篇
  1990年   1799篇
  1989年   1671篇
  1988年   1597篇
  1987年   1595篇
  1986年   1681篇
  1985年   2433篇
  1984年   2306篇
  1983年   2100篇
  1982年   1967篇
  1981年   1906篇
  1980年   1871篇
  1979年   1792篇
  1978年   1629篇
  1977年   1614篇
  1976年   1379篇
  1975年   1268篇
  1974年   1187篇
  1973年   1188篇
  1972年   898篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
We collected 469 frontal face images of Ukrainian cabinet ministers who were in office in 2000–2020. For each image, the minister's body mass index was estimated using a computer vision algorithm. The time series of median estimated body mass index of cabinet ministers co-moves over time with two existing measures of corruption – World Bank worldwide governance indicator Control of Corruption, and the discrepancy between the quantity of luxury wristwatches exported from Switzerland to Ukraine (reported by Swiss statistics) and the corresponding quantity imported by Ukraine from Switzerland (reported by Ukrainian statistics).  相似文献   
2.
3.
Prior research has shown that the well-being of employees engaged in intensive work can vary with the discretion their jobs afford regarding how and when to carry out the work. This article explores a different avenue. It argues that well-being also varies with employees’ individual motives for working intensively. The article introduces self-determination theory to the domain of work intensity and focuses on two hypotheses. The first is whether intensive work driven by explicit or implicit incentives is more positively associated with an employee's job satisfaction than intensive work driven by job demands. The second is whether intensive work driven by intrinsic motives is more positively associated with job satisfaction than that driven by explicit or implicit incentives. In both these cases, the article also examines whether equivalent effects exist on (reduced) quit intentions. Original data from a major Greek grocery chain provide corroborative evidence that is robust to a rich set of covariates, including increasingly demanding adjustments for job discretion. The findings contribute to a more complete understanding of why differences in well-being exist among employees performing intensive work, with implications for workers and employers.  相似文献   
4.
We investigate the impact of housing wealth, credit availability and financial distress on college enrolment decisions. We find that housing wealth is negatively related to enrolment in public schools and positively related to enrolment in private schools. This evidence suggests that, on average, students substituted away from private schools towards public institutions during the recent financial crisis.  相似文献   
5.
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   
6.
Growing urbanisation in South Africa is reflected in burgeoning Working class and informal township settlements on the fringes of its major towns and cities. Paired with this is an increasing reliance on cash as the primary means of economic transaction, which has in turn stimulated the growth of micro-enterprise business activities within the township context. This article discusses the findings of an eight-township small-area census which occurred between 2010 and 2013 in Cape Town, Johannesburg, Ekurhuleni and Durban townships representing 250 000 residents. The researchers were able to establish the scope and scale of informal food and drink retailing in these localities. Of the 10 049 micro-enterprises located in the study, some 3966 (or 39% of the total) trade in food. These include enterprises in primary production, fresh produce retailing, grocery retailing from house and spaza shops, and informal foodservice enterprises. Food is the basis for much township informal business and plays an important role in making food increasingly affordable and locally accessible, and in creating cash employment. The article builds on the knowledge base of the township informal economy role in bolstering food security needs for the marginalised.  相似文献   
7.
Consumer “multihoming” (watching two TV channels, or buying two news magazines) has surprisingly important effects on market equilibrium and performance in (two‐sided) media markets. We show this by introducing consumer multihoming and advertising finance into the classic circle model of product differentiation. When consumers multihome (attend more than one platform), media platforms can charge only incremental value prices to advertisers. Entry or merger leaves consumer prices unchanged under consumer multihoming, but leaves advertiser prices unchanged under single‐homing: Multihoming flips the side of the market on which platforms compete. In contrast to standard circle results, equilibrium product variety can be insufficient under multihoming.  相似文献   
8.
President Biden was sworn in on January 20, 2021 after a 4‐year term by President Trump. Certainly, Trump's norm breaking presidency impacted Canada in significant ways and the agricultural sector was no exception. In this issue, we have a set of four short articles discussing the possible implications on Canadian agriculture of transitioning from a Trump to Biden presidency. Issues related to Canada‐U.S. agricultural trade, political norms and uncertainty, U.S. domestic support, participation in trade agreements, and U.S.‐China relations are all considered.  相似文献   
9.
10.
Additive manufacturing (AM) appears to be a particularly attractive use case for blockchain. This research combines inductive in‐depth interviews with the Delphi method to explore what potentials blockchain technology in AM creates, which adoption barriers firms need to overcome, and how supply chains will be affected by the integration of these two potentially disruptive technologies. The results suggest opportunities that are related to intellectual property (IP) rights management, the monitoring of printed parts throughout their lifecycle, process improvements, and data security. The most important barriers for blockchain adoption in AM are an absence of blockchain‐skilled specialists on the labor market, missing governance mechanisms, and a lack of firm‐internal technical expertise. By addressing important limitations of AM, blockchain is expected to improve the competitiveness of AM in parts’ production, catalyzing the trend toward more decentralized manufacturing resulting in more agile, resilient, and flexible supply chains and reduced logistics costs. Beyond that, blockchain‐based AM platforms are expected to enhance supply chain visibility, drive supply chain digitalization, support supply chain finance, and contribute to the emergence of shared factory systems.  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