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   14338篇
  免费   324篇
财政金融   3014篇
工业经济   1074篇
计划管理   2330篇
经济学   3052篇
综合类   153篇
运输经济   112篇
旅游经济   239篇
贸易经济   2275篇
农业经济   626篇
经济概况   1773篇
信息产业经济   2篇
邮电经济   12篇
  2023年   74篇
  2021年   85篇
  2020年   196篇
  2019年   261篇
  2018年   349篇
  2017年   339篇
  2016年   314篇
  2015年   204篇
  2014年   331篇
  2013年   1625篇
  2012年   385篇
  2011年   470篇
  2010年   425篇
  2009年   445篇
  2008年   408篇
  2007年   362篇
  2006年   334篇
  2005年   263篇
  2004年   273篇
  2003年   279篇
  2002年   274篇
  2001年   280篇
  2000年   293篇
  1999年   297篇
  1998年   302篇
  1997年   265篇
  1996年   223篇
  1995年   220篇
  1994年   240篇
  1993年   241篇
  1992年   263篇
  1991年   253篇
  1990年   205篇
  1989年   188篇
  1988年   171篇
  1987年   165篇
  1986年   173篇
  1985年   246篇
  1984年   256篇
  1983年   245篇
  1982年   217篇
  1981年   197篇
  1980年   169篇
  1979年   171篇
  1978年   159篇
  1977年   133篇
  1976年   130篇
  1975年   140篇
  1974年   99篇
  1973年   100篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
Increased AIDS mortality and other preexisting conditions have contributed to agricultural productivity declines in the districts of Masaka and Rakai in Uganda. These two districts were the most fertile in Uganda and also had the highest HIV seroprevalence rates in Africa. 66% of study households experienced land use decline to some extent over the past 5 years. The 11% decline in poultry production and 32% decline in cattle production was reportedly due to poor management and loss of grazing land from overpopulation and larger scale farms. The most frequently reported reasons for crop reductions were death and sickness; these was estimated as affecting 8% of families with children under 5 years in the study area. Morbidity and mortality as a reason for the decline was reported two times as much as poverty and decline in international coffee prices. Other reasons for loss of productivity were food shortages and insecurity, loss of income, and reduced ability to respond to educational and medical needs. Cassava is replacing the culturally preferred matooke banana as a crop that is more disease-, pest-, and drought resistant. The banana weevil has been a recent problem. Marginal farming systems have been the most affected by declines in land use and livestock production, but fertile areas have not been spared the impact from AIDS and adult mortality. Poverty has decreased the use of pesticides, herbicides, and fertilizers in the districts. Policy has had an impact on agricultural practices: population growth and inheritance have added to loss of individual land holdings and contributed to fallow periods and infertility. Appropriate land management practices have not been adequately promoted in the agricultural extension service. Civil wars and the drop in coffee prices have reduced the number of farm laborers. Common grazing land has been turned over to large commercial ranches. Government should maintain research and monitoring of declines in food and cash crop production and manpower needs. Policy must be designed to respond to the complicated factors affecting productivity. High AIDS prevalence areas and marginal areas where reduced production effects would be the most severe must be given priority status. Development of cash crop alternatives must be examined and perhaps supported on an experimental basis by donor agencies. Maximum productivity should be encouraged by rural extension and education agencies. A number of other specific recommendations were made for individual survival strategies to maintain high agricultural productivity.  相似文献   
112.
The North American Waterfowl Management Plan seeks to improve wildlife habitat and increase waterfowl numbers through voluntary transactions with farmers to modify their land management practices. The impact of modified land use practices on the incomes of participating farmers and the regional economy are estimated. The compensation offered under the Plan for modification of land use is determined to adequately offset any loss in participants' income. Income losses to the community due to reduced farm input sales were more than offset by the increase in NAWMP direct expenditures (excluding compensation payments). Distributional effects and externalities must be recognized and monitored to ensure success of the program  相似文献   
113.
114.
In One destiny: Our common future in Africa the author relates, in popular fashion, a series of incidents which convinced him that the basic difference between black and white in South Africa is cultural deep‐seated and the cause of underdevelopment and conflict He develops a circular argument in which world‐view is taken as the root of perceptions, values and activities. The effects of experience and economic and political factors are given secondary importance. This argument cannot accommodate social change and differentiation, and the author tends to concentrate on perceptions and events which he finds morally unacceptable. He gives an unbalanced assessment and an ethnocentric interpretation of African life. Possible reasons for this type of argument are explored and an alternative which takes its departure from the interaction between experience and perception is offered  相似文献   
115.
Identifying the value orientations of subjects participating in market or non-market decisions by having them participate in a ring game may be helpful in understanding the behaviour of these subjects. This experiment presents the results of changes in the centre and the radius of a value orientations ring in an attempt to discover if the measured value orientations exhibit income or displacement effects. Neither significant income effects nor displacement effects are identified. An external validity check with a voluntary contribution game provides evidence that value orientations from rings centred around the origin of the decision-space explain significant portions of voluntary contributions while value orientations from displaced rings do not.  相似文献   
116.
Integration has been recognized as critical to successful supply chain management. However, an extensive literature review revealed no consensus in its conceptualization. The current study attempts to address this research gap by providing a better definition and operationalization of supply chain process integration. With empirical support, it is proposed that internal and external supply chain process integration should be treated as two separate constructs, each comprised of two dimensions: connectivity and simplification.  相似文献   
117.
We present new empirical evidence on the contextual nature of the predictive power of five statistically-based quarterly earnings expectation models evaluated on a holdout period spanning the twelve quarters from 2000–2002. In marked contrast to extant time-series work, the random walk with drift (RWD) model provides significantly more accurate pooled, one-step-ahead quarterly earnings predictions for a sample of high-technology firms (n = 202). In similar predictive comparisons, the Griffin-Watts (GW) ARIMA model provides significantly more accurate quarterly earnings predictions for a sample of regulated firms (n = 218). Finally, the RWD and GW ARIMA models jointly dominate the other expectation models (i.e., seasonal random walk with drift, the Brown-Rozeff (BR) and Foster (F) ARIMA models) for a default sample of firms (n = 796). We provide supplementary analyses that document the: (1) increased frequency of the number of loss quarters experienced by our sample firms in the holdout period (2000–2002) vis-à-vis the identification period (1990–1999); (2) reduced levels of earnings persistence for our sample firms relative to earnings persistence factors computed by Baginski et al. (2003) during earlier time periods (1970s–1980s); (3) relative impact on the predictive ability of the five expectation models conditioned upon the extent of analyst coverage of sample firms (i.e., no coverage, moderate coverage, and extensive coverage); and (4) sensitivity of predictive performance across subsets of regulated firms with the BR ARIMA model providing the most accurate predictions for utilities (n = 87) while the RWD model is superior for financial institutions (n = 131).
Kenneth S. Lorek (Corresponding author)Email:
G. Lee WillingerEmail:
  相似文献   
118.
119.
A major component of the United States Environmental Protection Agency's 112(r) Risk Management Program Rule is the evaluation and control of potential public exposures to toxic chemicals. The rule requires identification and evaluation of a worst case accidental toxic release scenario, but provides for the inclusion of passive mitigation systems in modeling the dispersion hazard zones that are to be communicated to the public. These passive mitigation systems can be taken into account in the consequence modeling if they will withstand the initiating event that causes the accidental release and function as intended. This paper discusses several passive mitigation systems that can be designed as an integral part of storage or processing of highly toxic chemicals. These include, but are not limited to, optimizing storage conditions, design of secondary containment, toxic vapor generation control, and enclosure design. The effectiveness of various passive mitigation systems is evaluated using consequence modeling for case studies involving highly toxic chemicals such as phosgene, chlorine, and ethylene oxide.  相似文献   
120.
In order to cut costs while increasing customer responsiveness, some corporations are integrating the competitive features of small companies with the resources of large corporations. They are adopting a hybrid type of organization by decentralizing decisionmaking to the business units and centralizing administrative functions at the corporate level. This article outlines the characteristics of a hybrid corporation and describes the role of corporate staffs within five corporations that have evolved to a hybrid structure. Some first steps on the path to a hybrid structure and corresponding staff activities are also described. © 1996 by John Wiley & Sons, Inc.  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