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   5373篇
  免费   1243篇
财政金融   1023篇
工业经济   493篇
计划管理   1252篇
经济学   1190篇
综合类   35篇
运输经济   117篇
旅游经济   94篇
贸易经济   1517篇
农业经济   327篇
经济概况   559篇
邮电经济   9篇
  2023年   12篇
  2022年   14篇
  2021年   94篇
  2020年   181篇
  2019年   520篇
  2018年   275篇
  2017年   401篇
  2016年   390篇
  2015年   412篇
  2014年   415篇
  2013年   721篇
  2012年   426篇
  2011年   388篇
  2010年   352篇
  2009年   262篇
  2008年   266篇
  2007年   219篇
  2006年   197篇
  2005年   161篇
  2004年   148篇
  2003年   129篇
  2002年   134篇
  2001年   111篇
  2000年   83篇
  1999年   46篇
  1998年   30篇
  1997年   20篇
  1996年   16篇
  1995年   21篇
  1994年   11篇
  1993年   16篇
  1992年   17篇
  1991年   8篇
  1990年   14篇
  1989年   6篇
  1988年   9篇
  1987年   7篇
  1986年   9篇
  1985年   18篇
  1984年   10篇
  1983年   6篇
  1982年   5篇
  1981年   3篇
  1980年   6篇
  1979年   7篇
  1978年   4篇
  1977年   3篇
  1976年   4篇
  1975年   3篇
  1968年   2篇
排序方式: 共有6616条查询结果,搜索用时 349 毫秒
131.
The univariate statistical properties of agricultural price series need to be examined as a first step in the analysis of price transmission mechanisms. However, in the case of weekly price series, increasingly available, the testing procedures usually applied in this step are not suitable to deal with evolving seasonal effects. In this study, a method of testing for seasonal unit roots in weekly series of agricultural prices is described. When the deterministic seasonal component does not remain constant over time, the restricted evolving spline model (RESM) is shown to be a useful parametric formulation to capture the deterministic seasonal pattern. Therefore, the RESM model should be included as a deterministic component in auxiliary regression for unit root tests at seasonal frequencies. This proposal is applied to three weekly series of Canary Islands banana prices. From the standard seasonal unit root tests, the null hypothesis is failed to be rejected at the 5% or 10% significance level at some seasonal frequencies for each one of the series. Once critical values are obtained by simulation exercises when the RESM model is included, the hypotheses of unit root are rejected at each one of the seasonal frequencies for all of the three series.  相似文献   
132.
Poor relief has received less attention from historians of southern Europe compared with northern Europe. This article seeks to challenge the frequent assumption that the strength of family ties in southern Europe mitigated the need for welfare provision. It provides new data for men and boys entering the Barcelona workhouse in the period 1780–1803, and compares these with data from an earlier study of women and girls who entered the same institution over the period 1762–1805. We establish the characteristics of those who sought relief in terms of age, place of origin, marital status, and occupation. We use the information on reasons for entry and exit to ascertain family circumstances. We show that there were significant differences between males and females in terms of why they entered and left, and length of stay, particularly among the elderly. The bulk of the population of the workhouse, however, was comprised of children and adolescents. For this group, entry into the workhouse represented not just a temporary solution to life cycle poverty and periodic unemployment, but also a longer‐term strategy aimed at smoothing entry into the labour market.  相似文献   
133.
Aims: To better understand the impact of the clinical course of multiple sclerosis (MS) and disability on employment, absenteeism, and related factors.

Materials and methods: This study included respondents to the North American Research Committee on Multiple Sclerosis Registry spring 2015 update survey who were US or Canadian residents, aged 18–65 years and reported having relapsing-remitting MS (RRMS), secondary progressive MS (SPMS), or primary progressive MS (PPMS). The RRMS and SPMS participants were combined to form the relapsing-onset MS (RMS) group and compared with the PPMS group regarding employment status, absenteeism, and disability. Multivariable logistic regression was used to examine the relationship between employment-related outcomes and factors that may affect these relationships.

Results: Of the 8004 survey respondents, 5887 (73.6%) were 18–65 years of age. The PPMS group (n?=?344) had a higher proportion of males and older mean age at the time of the survey and at time of diagnosis than the RMS group (n?=?4829). Female sex, age, age at diagnosis, cognitive and hand function impairment, fatigue, higher disability levels, ≥3 comorbidities, and a diagnosis of PPMS were associated with not working. After adjustment for disability, the employed PPMS sub-group reported similar levels of absenteeism to the employed RMS sub-group.

Limitations: Limitations of the study include self-report of information and the possibility that participants may not fully represent the working-age MS population.

Conclusions: In MS, employment status and absenteeism are negatively affected by disability, cognitive impairment, and fatigue. These findings underscore the need for therapies that prevent disability progression and other symptoms that negatively affect productivity in persons with MS to enable them to persist in the workforce.  相似文献   
134.
135.
The BRICS countries in general, and China and India in particular, are now widely regarded as the areas of the world likely to challenge the economic leadership of the United States (US) and the European Union (EU). A large part of this challenge will come from rapid technological catch‐up by China and India. Yet, despite a recent rise in interest, there is limited knowledge about how and where innovation takes place in these two leading emerging countries and to what extent the Chinese and Indian territorial systems of innovation differ from those in the EU or the US. In this article we explore the geography of innovation in China and India, concentrating on understanding key territorial‐level innovation trends by country, region and technology field, using the US and the EU as benchmarks. We find significant contrasts between the geography of innovation in China and India and that of the US and the EU. First, the degree of concentration of innovative activities in both countries is extremely high. Levels of agglomeration of innovation in the coastal provinces of China, as well as in Delhi and the South of India, significantly exceed the levels of agglomeration found in the USA and the EU. Secondly, China has witnessed a more rapid increase in the degree of concentration of innovation than India. We posit that the differences in the geography of innovation between, on the one hand, China and India and, on the other hand, between these countries and the developed world are rooted in different institutional settings, different systems of innovation and different national innovation strategies.  相似文献   
136.
This study investigates the performance of analysts when they match the asymmetric timeliness of their earnings forecast revisions (i.e., asymmetric forecast timeliness) with the asymmetric timeliness of firms’ reported earnings (i.e., asymmetric earnings timeliness). We find that better timeliness‐matching analysts produce more accurate earnings forecasts and elicit stronger market reactions to their forecast revisions. Further, better timeliness‐matching analysts issue less biased earnings forecasts, more profitable stock recommendations and have more favorable career outcomes. Overall, our results indicate that analysts’ ability to incorporate conditional conservatism into their earnings forecasts is an important reflection of analyst expertise and professional success.  相似文献   
137.
Many environmental problems are due to damage caused by pollutants that accumulate with a time lag following their emission. In this study, we focus on nitrates used in agriculture, which can pollute groundwater many years after their initial application. A dynamic optimal control problem with heterogeneous farmers is proposed. The usual structural parameters such as the discount rate, the natural clearing rate and the lagged time interval between the occurrence of soil‐level pollution and the impact on groundwater are taken into account. We also examine pollution as caused by a continuous set of farms characterised by their individual performance index and by their individual marginal contribution to the pollution. The issue is further investigated by taking account of change in the information context, successively related to perfect information and to asymmetric information. As a result, when the delay between the spreading of N‐fertilizer and the impact on the aquifer increases, that is, the longer the lag, the steady‐state pollution stock and the steady‐state shadow price of the stock both increase. Moreover, we show that the optimal regulation may require a decreasing amount of fertilizer over time, even in the case of initial underpollution.  相似文献   
138.
It was analysed whether investment in the education of both women and men serves to empower wives resulting in more balanced household decisions being taken on matters related to consumption and financial management. They considered that household decision‐making could be made by mainly the wife, mainly the husband or the couple acting jointly. They then applied multinomial probit models to the Spanish Living Conditions Survey of 2010. Results show that, when controlling for demographic, family and labour market characteristics, the level of education of both the husband and wife has a positive effect in terms of a more egalitarian decision‐making process in relation to three areas of expenditure: daily shopping, expensive purchases of consumer durables and significant expenditure on children. However, only women's education has a positive effect on borrowing money and no effect of education is observed with regard to the use of savings. Results are less conclusive for households where decisions are taken primarily by the wife or husband, since men's education increases the role of husbands in the household making‐decision process whereas no effect of wives' education is observed.  相似文献   
139.
Most studies of input subsidy programmes confine their analyses to measuring programme effects over a one‐year period. This article estimates the potential longer‐run or enduring effects of fertiliser subsidy programmes on smallholder farm households' demand for commercial fertiliser and maize production over time. We use four waves of panel data on 462 farm households in Malawi for whom fertiliser use can be tracked for eight consecutive seasons between 2003/2004 and 2010/2011. Panel estimation methods are used to control for potential endogeneity of subsidised fertiliser acquisition. Results indicate that farmers acquiring subsidised fertiliser in three consecutive prior years are found to purchase slightly more commercial fertiliser in the next year. This suggests a small amount of crowding in of commercial fertiliser from the receipt of subsidised fertiliser in prior years. In addition, acquiring subsidised fertiliser in a given year has a modest positive impact on increasing maize output in that same year. However, acquiring subsidised fertiliser in multiple prior years generates no statistically significant effect on maize output in the current year. These findings indicate that potential enduring effects of the Malawi fertiliser subsidy programme on maize production are limited. Additional interventions that increase soil fertility can make using inorganic fertiliser more profitable and sustainable for smallholders in sub‐Saharan Africa and thereby increase the cost‐effectiveness of input subsidy programmes.  相似文献   
140.
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