全文获取类型
收费全文 | 12554篇 |
免费 | 220篇 |
专业分类
财政金融 | 2207篇 |
工业经济 | 867篇 |
计划管理 | 2099篇 |
经济学 | 2663篇 |
综合类 | 98篇 |
运输经济 | 79篇 |
旅游经济 | 172篇 |
贸易经济 | 1950篇 |
农业经济 | 706篇 |
经济概况 | 1891篇 |
信息产业经济 | 1篇 |
邮电经济 | 41篇 |
出版年
2020年 | 113篇 |
2019年 | 182篇 |
2018年 | 272篇 |
2017年 | 250篇 |
2016年 | 247篇 |
2015年 | 158篇 |
2014年 | 267篇 |
2013年 | 1093篇 |
2012年 | 352篇 |
2011年 | 358篇 |
2010年 | 304篇 |
2009年 | 355篇 |
2008年 | 345篇 |
2007年 | 295篇 |
2006年 | 287篇 |
2005年 | 246篇 |
2004年 | 251篇 |
2003年 | 241篇 |
2002年 | 253篇 |
2001年 | 222篇 |
2000年 | 251篇 |
1999年 | 219篇 |
1998年 | 206篇 |
1997年 | 190篇 |
1996年 | 203篇 |
1995年 | 182篇 |
1994年 | 194篇 |
1993年 | 191篇 |
1992年 | 210篇 |
1991年 | 207篇 |
1990年 | 210篇 |
1989年 | 178篇 |
1988年 | 144篇 |
1987年 | 152篇 |
1986年 | 169篇 |
1985年 | 248篇 |
1984年 | 224篇 |
1983年 | 196篇 |
1982年 | 199篇 |
1981年 | 200篇 |
1980年 | 188篇 |
1979年 | 189篇 |
1978年 | 166篇 |
1977年 | 153篇 |
1976年 | 148篇 |
1975年 | 151篇 |
1974年 | 116篇 |
1973年 | 114篇 |
1972年 | 106篇 |
1971年 | 83篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
111.
Metallic structured packings have found increasing use in the cryogenic distillation of air. An experimental program was performed to test the flammability of selected metal packings under simulated high oxygen concentration operating conditions. Aluminum flammability in gaseous oxygen has been shown to be very dependent upon argon dilution, and in the presence of liquid oxygen, strong energy releases have been observed. Brass packing exhibited an unexpectedly high relative flammability whereas copper has been found to be non-flammable in all tested oxygen purities. These findings suggest the use of copper structured packing in higher purity GOX/LOX regions of an air separation distillation column and aluminum structured packing in the remainder of the column. 相似文献
112.
A. G. Barve 《The World Economy》1991,14(2):239-242
Dynamics and Conflict in Regional Structura1 Change—Essay in Honor of Walter Isard Volume 2 Practical Methods of Regional Science and Empirical Applications—Selected Papers of Walter Isard, Volume 2 Department of Economics Loughborough University Export Promotion Strategies—Theory and Evidence from Developing Countries Commonwealth Secretariat Export Market Development Division Human Development Report 1990 for the United Nations Development Programme (UNDP) (New York and Oxford: University of Nottingham The World Bank and the Environment—First Annual Report Fiscal 1990, The World Bank (New York: The World Bank, 1990 London Environmental Economics Centre University College London The European Communities' Single Market: The Challenge of 1992 for Sub-Saharan Africa Loughborough University 相似文献
113.
Thomas G. Grumbles 《Process Safety Progress》1990,9(2):87-90
This paper presents the results of an industry survey that was sponsored by the Ethylene Oxide Industry Council (EOIC). The EOIC operates as a special program of the Chemical Manufacturers Association. The members of EOIC account for over 85 percent of domestic production of EtO and cover a broad range of EtO users, including ethoxylators and sterilizers. The survey was done to collect current information in anticipation of responding to a proposed OSHA rulemaking for a short-term exposure limit for EtO. Specifically, the study was designed to collect information on the following:
- 1. History of the establishment of company EtO exposure guidelines.
- 2. Current EtO workplace exposure monitoring practices, capabilities and methods.
- 3. Current workplace exposure levels: Eight hour and short-term.
- 4. Engineering control, respirator, and ancillary costs for compliance with the 1.0 Permissible Exposure Limit (PEL) and projected costs for compliance with a 5.0 ppm or 10.0 ppm Short–term Exposure Limit (STEL).
114.
G. De Fraja 《Metroeconomica》1990,41(2):137-160
If the payoff obtained by the parties of an agreement depends on the values set for variables the value of which cannot be described precisely or monitored accurately, then the first best outcome may not be achieved. It is shown here that in some cases a second best long term agreement gives the parties a higher payoff, in other cases a short term arrangement is preferred. The interpretation of this result given in the paper is that when a long term contract is preferable, then firms are unable to commit themselves to it through a collusive agreement, and they will try to merge. Vice versa, no need to integrate arises when the preferred second best agreement is the short term one. The last section provides an example, where advertisement effort is non-contractible, while prices are. 相似文献
115.
Paul G. Chapman 《Metroeconomica》1990,41(3):249-258
A two period model of the training decision is analysed using a human capital approach. The segmented labour market model where training opportunities distinguish entrants is compared with a competitive structure with homogeneous entrants. The main conclusions in the paper are the clear effects of training wages and the different effects in the two market structures of both wages and employment prospects in the unskilled market on training. 相似文献
116.
Great hopes have been placed in the sharing economy to provide a new business model based on peer-to-peer (P2P) exchanges of underutilized assets. As a model, the sharing economy has been expected to make significant contributions to sustainability, providing new opportunities for entrepreneurship, more sustainable use of resources, and consumer co-operation in tight economic networks. However, in recent years, digital platforms have turned into the most important actors in the global sharing economy, turning global corporations, such as AirBnB, Booking, or TripAdvisor into intermediaries controlling and profiting from most transactions. Focused on accommodation, this paper conceptualizes the sharing economy in comparison to the wider collaborative economy, and discusses its social, economic, environmental, and political impacts in comparison to the sustainable development goals. It concludes that the sharing economy has great potential to make very significant contributions to sustainability, though the model is increasingly being replaced by the collaborative economy, which performs as an extension and acceleration of neoliberal economic practices. 相似文献
117.
Before embarking on the development of rural areas or regions it seems necessary to answer the following key questions: what goals of the parties involved can be realized, and where, when and how? To tackle these questions we have developed a ‘roadmap’, as part of an overall sustainable development procedure for physical planning and spatial management in rural areas. The roadmap is a tool for the process manager and the people involved. It helps to find the way in the exploration of the potential social, economic and ecological benefits of developing the area or region. The purpose of using the roadmap is to alleviate doubts about the advantages of cooperating in pursuit of sustainable development. A back-casting approach is applied to create appealing visions of the future and visualize mutual opportunities worth implementing. In this article we first describe the need for this new roadmap. We then describe its use, step by step and in some detail. An example of the exploration process is described and the strengths and weaknesses of the roadmap are discussed. 相似文献
118.
The purpose of this study is to identify generational differences and similarities among hospitality employees and managers in order to develop leadership strategies and management styles that can be utilized to increase employee morale and productivity while enhancing recruitment and retention rates of highly qualified workers. Data for this study were collected through a series of in-depth focus group discussions. Findings indicated significant generational differences in world views, attitudes toward authority and perspectives on work. Findings suggested the Baby Boomers respect authority and hierarchy, while the Generation X-ers (Gen X-ers) rebel against authority. Findings also suggested while Baby Boomers live to work, Gen X-ers work to live. The Baby Boomers are willing to wait their turn for promotions and rewards, and are very loyal. On the other hand, Gen X-ers expect immediate recognition through title, praise, promotion, and pay. They also want a life outside of work—they are not likely to sacrifice theirs for the company. The Millennial Generation believes in collective action, with optimism of the future, and trust in centralized authority. They like teamwork, showing a strong will to get things done with a great spirit. 相似文献
119.
120.