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   151488篇
  免费   4370篇
  国内免费   27篇
财政金融   25700篇
工业经济   11629篇
计划管理   21884篇
经济学   29397篇
综合类   1483篇
运输经济   958篇
旅游经济   2481篇
贸易经济   23580篇
农业经济   6117篇
经济概况   16947篇
水利工程   15453篇
信息产业经济   7篇
邮电经济   249篇
  2021年   1071篇
  2020年   1803篇
  2019年   2619篇
  2018年   2718篇
  2017年   2771篇
  2016年   3088篇
  2015年   2357篇
  2014年   3782篇
  2013年   16290篇
  2012年   4783篇
  2011年   4581篇
  2010年   4046篇
  2009年   4704篇
  2008年   4287篇
  2007年   3762篇
  2006年   4102篇
  2005年   3940篇
  2004年   3559篇
  2003年   3104篇
  2002年   3116篇
  2001年   2941篇
  2000年   2788篇
  1999年   2694篇
  1998年   2534篇
  1997年   2615篇
  1996年   2471篇
  1995年   2261篇
  1994年   2268篇
  1993年   2250篇
  1992年   2340篇
  1991年   2189篇
  1990年   2045篇
  1989年   1923篇
  1988年   1818篇
  1987年   1826篇
  1986年   1847篇
  1985年   2644篇
  1984年   2550篇
  1983年   2357篇
  1982年   2225篇
  1981年   2158篇
  1980年   2185篇
  1979年   2090篇
  1978年   1893篇
  1977年   1823篇
  1976年   1648篇
  1975年   1483篇
  1974年   1405篇
  1973年   1410篇
  1972年   1107篇
排序方式: 共有10000条查询结果,搜索用时 906 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.
Water Resources Management - The water evaluation and planning (WEAP) approach and the invasive weed optimization algorithm (IWOA) are herein employed to determine the optimal operating policies in...  相似文献   
3.
4.
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   
5.
3月22日是第二十八届“世界水日”,第三十三届“中国水周”的宣传活动也同时拉开帷幕。联合国确定今年“世界水日”的宣传主题是“水与气候变化”,我国纪念“世界水日”和开展“中国水周”活动的宣传主题是“坚持节水优先,建设幸福河湖”。党的十八大以来,以习近平同志为核心的党中央高度重视水利工作。习近平总书记多次就治水发表重要讲话、作出重要指示,明确提出“节水优先、空间均衡、系统治理、两手发力”的治水思路,对长江经济带共抓大保护、不搞大开发,黄河流域共同抓好大保护、协同推进大治理等作出重要部署,发出了建设造福人民的幸福河的伟大号召,为推进新时代治水提供了科学指南和根本遵循。  相似文献   
6.
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   
7.
8.
This paper presents an approach to assessing the efficacy of public spending on research and development in state programs. At present, there is a need to develop a unified approach to the analysis and evaluation of the efficacy of such spending from the perspective of participants in state programs (federal executive bodies). The proposed approach does not allow evaluating the efficacy of public spending on the development of research areas assigned to the authors.  相似文献   
9.
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   
10.
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