全文获取类型
收费全文 | 14681篇 |
免费 | 413篇 |
国内免费 | 3篇 |
专业分类
财政金融 | 3048篇 |
工业经济 | 1094篇 |
计划管理 | 2398篇 |
经济学 | 3151篇 |
综合类 | 207篇 |
运输经济 | 105篇 |
旅游经济 | 228篇 |
贸易经济 | 2346篇 |
农业经济 | 653篇 |
经济概况 | 1852篇 |
信息产业经济 | 2篇 |
邮电经济 | 13篇 |
出版年
2023年 | 83篇 |
2021年 | 109篇 |
2020年 | 222篇 |
2019年 | 275篇 |
2018年 | 358篇 |
2017年 | 348篇 |
2016年 | 327篇 |
2015年 | 218篇 |
2014年 | 351篇 |
2013年 | 1628篇 |
2012年 | 442篇 |
2011年 | 541篇 |
2010年 | 481篇 |
2009年 | 480篇 |
2008年 | 442篇 |
2007年 | 397篇 |
2006年 | 359篇 |
2005年 | 286篇 |
2004年 | 277篇 |
2003年 | 277篇 |
2002年 | 276篇 |
2001年 | 283篇 |
2000年 | 291篇 |
1999年 | 295篇 |
1998年 | 301篇 |
1997年 | 264篇 |
1996年 | 222篇 |
1995年 | 219篇 |
1994年 | 235篇 |
1993年 | 239篇 |
1992年 | 263篇 |
1991年 | 252篇 |
1990年 | 202篇 |
1989年 | 183篇 |
1988年 | 165篇 |
1987年 | 162篇 |
1986年 | 167篇 |
1985年 | 237篇 |
1984年 | 256篇 |
1983年 | 244篇 |
1982年 | 211篇 |
1981年 | 195篇 |
1980年 | 169篇 |
1979年 | 167篇 |
1978年 | 156篇 |
1977年 | 133篇 |
1976年 | 123篇 |
1975年 | 139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
991.
It is argued in this article that sub-Saharan Africa, given its present institutions and endowments of capital and technology, is already dangerously close to overpopulation. The rapid growth of its population projected for the next decades will greatly increase human misery and depress economic development. Specifically, rapid population growth will have disastrous effects on the region's ability to increase exports and provide people with food. There must be a search for new ways in which these effects could be mitigated. In sub-Saharan Africa fertility either continues to be very high or is increasing, in part due to some decline in traditional practices that reduce fertility, such as prolonged breastfeeding. This situation and the expectation of declining mortality imply that African population growth may increase further. Currently, population in sub-Saharan Africa is about half that of India and a third of China. There are 2 main reasons why reduced fertility in the next few decades is unlikely in sub-Saharan Africa as a whole: Africa has low literacy, high infant and child mortality, and low urbanization; and average African fertility rates may even increase for the next 20 years or so. The question that arises is what are the implications of continuing and rapid population growth for the African food supply. The region's cereal production is largely restricted to 4 grains, i.e., millet, sorghum, maize, and rice. The volume of grain production is less, by weight, than 60% of the production of roots and tubers. There are 2 main differences between the output of these crops in sub-Saharan Africa and the rest of the world: yields/hectare are lower in Africa than in elsewhere; and yields have generally been decreasing or largely constant in Africa. The low productivity has several causes. Today, population pressure has brought diminishing returns to traditional agriculture in much of the Sahel and the savanna, in parts of East Africa, Southern Africa, and parts of the West African forest belt. There is also the absence of the Green Revolution, i.e., the use of new high yielding seeds and new technologies in agriculture that has led to marked increases in yields in most other parts of the world. A totally different and more productive agriculture might evolve if African governments were to fundamentally change their vision. Existing production technology could allow substantial increases in the yields of many crops if some basic changes were made in the policies affecting agriculture. A way to achieve such change would be to make farming profitable. The effect of population growth in diminishing returns to agriculture also lends urgency to the need for family planning. Generally, population policy in Africa badly needs strengthening. 相似文献
992.
993.
Abstract: The passage of California's Proposition 103 in November 1988 changed the State's regulatory structure for insurers from a competitive to a heavily regulated system. The six-year legal battle that followed resulted in several California Supreme Court and United States Supreme Court rulings and an ultimate implementation of rate roll backs on property-liability insurers on November 22, 1994. The study examines both property-liability and life insurers' returns. While only property-liability insurers are affected by the rale rollback and prior approval rate regulation, both life and property-liability insurers are affected by the proposition's other provisions. This paper examines the effect of successive changes on both types of insurance companies and analyzes the differential impact of the changes in regulatory structure. 相似文献
994.
We explore the effects of uncertainty on a firm that can respond by modifying its investment or production schedule (or both simultaneously) to variations in output price. Investment may increase capacity and/or reduce costs. We consider a firm with finite resources.Our model uses option theory instead of the more traditional net present value framework. One of the early papers using this approach is Brennan and Schwartz (1985) in which an investment project to extract a finite natural resource is valued. In that paper, the value of the firm is a function of two state variables, the finite resource to be extracted (output to be produced in the future) and the commodity spot price. In order to maximize firm value, the manager can respond by modifying one control variable, the production level. In our model we handle instead three state variables (spot price, resources, accumulated investment) and two control variables (production rate and investment rate), and solve numerically.We obtain both the value and the optimal policy of a firm that has investment projects that increase capacity and/or reduce costs and illustrate optimal policies as resources and available investments decrease over the life of the firm. Firms may start by only investing, then invest and produce, to end only producing.We thank Scott Wo, the referee and the editor for their comments and suggestions. Cortázar and Lowener acknowledge the financial support from FONDECYT and FONDER. 相似文献
995.
Residual income subtracts from operating income an interest charge for invested capital. Residual income can be calculated each period from current accounting information, unlike discounted cash flow (DCF), which requires the knowledge of future cash flows. This paper provides a normative justification for residual-income maximization by showing that if investment decisions are made myopically each period to maximize residual income, the resulting path asymptotically maximizes discounted cash flow. Thus, under the assumptions of the model, residual-income maximization is a heuristic that leads to the long-run DCF-optimum. 相似文献
996.
Due to prevalent demographic factors, long-term care is an issue of increasing concern to American workers. The cost and time involved in ever-expanding long-term care responsibilities for many employees has resulted in increased indirect employer costs. The authors argue that providing' long-term care as part of the employee benefit plan is an efficient and effective way to manage these increasing costs for both the employer and the employee. The article offers discussion of plan design for long-term care, including issues to be considered and strategy for plan management. 相似文献
997.
This article presents a case study of how General Electric's Lighting Division has used the Internet to dramatically improve purchasing and logistics performance. By applying new techniques and technologies, including an Internet-based "Trading Process Network," GE Lighting has achieved substantial benefits, including cycle time reduction, elimination of paper and mail processing, improved information sharing with suppliers, quality improvement, and cost reduction. 相似文献
998.
999.
1000.