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   1173篇
  免费   45篇
财政金融   282篇
工业经济   88篇
计划管理   205篇
经济学   177篇
综合类   8篇
运输经济   15篇
旅游经济   33篇
贸易经济   210篇
农业经济   65篇
经济概况   135篇
  2022年   7篇
  2021年   9篇
  2020年   19篇
  2019年   24篇
  2018年   31篇
  2017年   25篇
  2016年   32篇
  2015年   20篇
  2014年   20篇
  2013年   198篇
  2012年   24篇
  2011年   33篇
  2010年   38篇
  2009年   28篇
  2008年   39篇
  2007年   33篇
  2006年   26篇
  2005年   31篇
  2004年   31篇
  2003年   36篇
  2002年   32篇
  2001年   21篇
  2000年   29篇
  1999年   19篇
  1998年   28篇
  1997年   24篇
  1996年   12篇
  1995年   13篇
  1994年   18篇
  1993年   14篇
  1992年   17篇
  1991年   14篇
  1990年   16篇
  1989年   16篇
  1988年   9篇
  1987年   11篇
  1986年   18篇
  1985年   25篇
  1984年   17篇
  1983年   19篇
  1982年   8篇
  1981年   18篇
  1980年   13篇
  1979年   16篇
  1978年   8篇
  1977年   11篇
  1976年   11篇
  1975年   9篇
  1974年   7篇
  1972年   7篇
排序方式: 共有1218条查询结果,搜索用时 31 毫秒
31.
This paper introduces computational estimation to the literature on consumers’ numerical cognition. Computational estimation involves simplifying an arithmetic problem via mathematical procedures to produce an approximate answer. Employing calculation knowledge and approximation together, consumers are likely to use computational estimation as it is relatively accurate while saving cognitive effort compared to calculating values. Three studies applied to partitioned prices in the form of a base price and a percentage discount, demonstrate that when faced with this numeric integration task, the strategy consumers undertake is dependent on the characteristics of the numerals with discounts that are round or close to round being associated with greater use of computational estimation. Further, when employing computational estimation, consumers arrive at more accurate, and lower, price estimates in which they place more confidence than when using alternative an integration strategy. As a result, discounts that are near a round value are preferred to those that are not; a result that is dependent upon the use of computational estimation.  相似文献   
32.
An econometric model is developed and estimated for all brands of coffee sold at the retail level in four supermarkets in Columbus, Ohio. These brands are segmented into 24 categories, and the four stores are classified into two groups, inner-city and suburban, based on 2010 census tract data. Using estimated measures of price-sensitivity, these 24 categories are further segmented into four groups to help guide and clarify the discussion. Estimated results show different purchasing patterns and different levels of price-sensitivity for inner-city and suburban shoppers. Further, these purchasing patterns and levels of price-sensitivity suggest alternative marketing strategies for retailers. Private-label coffee brands are shown to be quite competitive with many national brands, and indeed private-label brands command a market share among inner-city shoppers that is more than double that for the nation (21.95% vs. 9%).  相似文献   
33.
Invasive animal pests reduce crop and livestock output, require management and control measures, and threaten native plants, animals and their habitat. The agricultural and management costs are often directly measurable. But the costs to protect threatened native plants and animals are harder to assess. The Rural Lands Protection Boards were the government agency in New South Wales that managed invasive animals. An analysis of their decisions provided the opportunity to estimate the costs of protecting native species. The number of native plants and animals threatened by invasive pests was modelled against the expenditure, area, pest abundance, climate and location of 38 Board districts. There was a strong negative relationship between the number of threatened native species and Board expenditure. This relationship was interpreted to estimate the marginal cost of protecting a threatened native species, the downward shift in the supply curve necessary to protect all threatened native species, and the gains from the shift in the form of cost savings in the continued protection of non-threatened native species. These results value some of the costs that invasive animal pests impose on the environment.  相似文献   
34.
Land-use change has a significant impact on the world’s ecosystems. Changes in the extent and composition of forests, grasslands, wetlands and other ecosystems have large impacts on the provision of ecosystem services, biodiversity conservation and returns to landowners. While the change in private returns to landowners due to land-use change can often be measured, changes in the supply and value of ecosystem services and the provision of biodiversity conservation have been harder to quantify. In this paper we use a spatially explicit integrated modeling tool (InVEST) to quantify the changes in ecosystem services, habitat for biodiversity, and returns to landowners from land-use change in Minnesota from 1992 to 2001. We evaluate the impact of actual land-use change and a suite of alternative land-use change scenarios. We find a lack of concordance in the ranking of baseline and alternative land-use scenarios in terms of generation of private returns to landowners and net social benefits (private returns plus ecosystem service value). Returns to landowners are highest in a scenario with large-scale agricultural expansion. This scenario, however, generated the lowest net social benefits across all scenarios considered because of large losses in stored carbon and negative impacts on water quality. Further, this scenario resulted in the largest decline in habitat quality for general terrestrial biodiversity and forest songbirds. Our results illustrate the importance of taking ecosystem services into account in land-use and land-management decision-making and linking such decisions to incentives that accurately reflect social returns.  相似文献   
35.
Charter value is important in the banking industry because of its ability to reduce the moral hazard incentives that result from government-provided deposit insurance. Previous research suggests that geographic deregulation in the 1970s and 1980s increased competition and eroded charter values. Yet, a common proxy for charter value, Tobin's Q, increased significantly in the 1990s and beyond even as bank deregulation continued. We show that Tobin's Q is a poor cardinal measure of charter value though it still has merit as an ordinal measure. Our findings suggest that charter value has been declining through time, contributing to the increase in risk-taking that led to the subprime financial crisis.  相似文献   
36.
On-line supervision exhibits in many respects properties complementary to those of established off-line safety tests. Thus, on-line methods are powerful tools for increasing the safety of chemical processes, especially in situations where unexpected hazards could occur. Known on-line supervising methods are described and their advantage and disadvantages are briefly discussed. The abilities of various on-line methods are demonstrated on a real case.  相似文献   
37.
The objective of this study was to conduct empirical comparisons between two models of optimal experience within an on-site whitewater kayaking setting using a modification of the Experience Sampling Method. Four concerns are examined: (1) differences in explanatory power between the four channel flow model and the Adventure Experience Paradigm, (2) convergent validity among measures used to determine conditions within these models, (3) differences among measures of perceived challenge and risk between test times of Class I-V river difficulty, and (4) differences among measures of perceived skill and competence between test times of Class I-V river difficulty. Questionnaires were administered in the Cheat River Canyon in West Virginia to 52 whitewater kayakers at eight sites of various levels of river difficulty. Data were analyzed at the experience level, rather than between subjects, using 409 experience sampling observations. Hypothesis testing, performed with statistical analyses (stepwise regression, correlations, and repeated measures ANOVA), suggested that the explanatory powers of the four channel flow model and Adventure Experience Paradigm were similar and indicated support for convergent and ecological validity of measures used to determine conditions within each of the two models.  相似文献   
38.
This paper describes dust explosibility research in full-scale experimental mines and a 20-L laboratory chamber at the U.S. Bureau of Mines and in a 1-m3 laboratory chamber at Fike Corporation. The purpose of this research is to improve safety in mining and other industries that manufacture, process, or use combustible dusts. As part of this work, carbonaceous dusts with a wide range of volatilities and various particle size distributions were studied. Laboratory data on the minimum explosible concentrations of predispersed dusts were comparable to mine data for nominal dust loadings that were dispersed by the aerodynamic disturbance from a gas ignition zone. Recommendations are given on the limitations of small-scale testing such as “overdriving” by too strong of an ignitor. The effect of dust particle size on explosibility data is illustrated for coal and aluminum dusts. For both dusts, the finest sizes were the most hazardous. The inerting requirements for preventing explosions were also measured in both laboratory and large-scale systems. All the data show relatively good agreement between the laboratory and the large-scale tests.  相似文献   
39.
40.
The case for promoting export‐oriented cash crops in Africa has generally been based on their direct potential contribution to agricultural productivity and small farmer incomes. A relatively neglected avenue of research concerns the synergistic effects that cash cropping can have on other household activities, including food production. The conventional view that cash crops compete with food crops for land and labour neglects the potential for cash crop schemes to make available inputs on credit, management training, and other resources that can contribute to food crop productivity, which might otherwise not be accessible to farmers if they did not participate in cash crop programs. This article builds on previous research by hypothesising key pathways by which cash crops may affect food crop activities and empirically measuring these effects using the case of cotton in Gokwe North District in Zimbabwe. Analysis is based on instrumental variable analysis of survey data on 430 rural households in 1996. Results indicate that—after controlling for household assets, education and locational differences—households engaging intensively in cotton production obtain higher grain yields than non‐cotton and marginal cotton producers. We also find evidence of regional spill‐over effects whereby commercialisation schemes induce second round investments in a particular area that provide benefits to all farmers in that region, regardless of whether they engage in that commercialisation scheme. The study suggests that the potential spill‐over benefits for food crops through participation in cash crop programs are important to consider in the development of strategies designed to intensify African food crop production.  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