全文获取类型
收费全文 | 17314篇 |
免费 | 471篇 |
国内免费 | 1篇 |
专业分类
财政金融 | 2938篇 |
工业经济 | 1297篇 |
计划管理 | 2565篇 |
经济学 | 3242篇 |
综合类 | 159篇 |
运输经济 | 120篇 |
旅游经济 | 270篇 |
贸易经济 | 2280篇 |
农业经济 | 712篇 |
经济概况 | 2078篇 |
水利工程 | 2121篇 |
信息产业经济 | 1篇 |
邮电经济 | 3篇 |
出版年
2021年 | 138篇 |
2020年 | 196篇 |
2019年 | 265篇 |
2018年 | 386篇 |
2017年 | 367篇 |
2016年 | 358篇 |
2015年 | 243篇 |
2014年 | 390篇 |
2013年 | 1721篇 |
2012年 | 616篇 |
2011年 | 601篇 |
2010年 | 487篇 |
2009年 | 569篇 |
2008年 | 571篇 |
2007年 | 571篇 |
2006年 | 553篇 |
2005年 | 474篇 |
2004年 | 492篇 |
2003年 | 325篇 |
2002年 | 310篇 |
2001年 | 320篇 |
2000年 | 339篇 |
1999年 | 300篇 |
1998年 | 276篇 |
1997年 | 285篇 |
1996年 | 267篇 |
1995年 | 238篇 |
1994年 | 241篇 |
1993年 | 278篇 |
1992年 | 252篇 |
1991年 | 262篇 |
1990年 | 241篇 |
1989年 | 230篇 |
1988年 | 216篇 |
1987年 | 198篇 |
1986年 | 216篇 |
1985年 | 299篇 |
1984年 | 277篇 |
1983年 | 274篇 |
1982年 | 242篇 |
1981年 | 232篇 |
1980年 | 247篇 |
1979年 | 202篇 |
1978年 | 175篇 |
1977年 | 165篇 |
1976年 | 150篇 |
1975年 | 131篇 |
1974年 | 112篇 |
1973年 | 111篇 |
1972年 | 84篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Decentralised systems have the potential to provide a viable option for long term sustainable management of household wastewater. Yet, at present, such systems hold an uncertain status and are frequently omitted from consideration. Their potential can only be realised with improved approaches to their management, and improved methods to decision-making in planning of wastewater systems. The aim of this paper is to demonstrate the value of a novel framework to guide the planning of decentralised systems so that asset management and risk management are explicitly considered. The framework was developed through a detailed synthesis of literature and practice in the area of asset management of centralised water and wastewater systems, and risk management in the context of decentralised systems. Key aspects of the framework are attention to socio-economic risks as well as engineering, public health and ecological risks, the central place of communication with multiple stakeholders and establishing a shared asset information system. A case study is used to demonstrate how the framework can guide a different approach and lead to different, more sustainable outcomes, by explicitly considering the needs and perspectives of homeowners, water authorities, relevant government agencies and society as a whole. 相似文献
72.
Increasing concern in recent years over the occurrence and fate of low-level concentrations of pharmaceuticals in the aquatic environment stimulates research on alternative treatment methods. This paper presents a study of the degradation of sulphamethoxazole, an antibiotic used on humans and animals in order to treat various bacterial infections, by ozonation. After 4.5 min of treatment, the concentration of sulphamethoxazole was below the HPLC detection limit of 0.6 mgL(-1), indicating degradation efficiency higher than 99.24%. This value is comparable and in some cases higher than published data on the degradation in drinking water. Kinetic analysis of the data indicated an overall first-order reaction with a rate constant of 1.0594 min(-1) at 20 degrees C. The reaction order differs with the second-order reaction observed by other researchers. This change of reaction order could be explained by the different treatment conditions used. Preliminary analysis using the FT-IR technique was also performed in order to obtain information on the structure of the degradation products. Further analysis using a GC-MS is needed in order to elucidate the structure of the degradation products. Finally, based on the experiments performed, ozonation seems to be a promising technique for the degradation of antibiotics, even in wastewater. 相似文献
73.
V C Hammen 《Water science and technology》2007,56(1):253-258
Smoke-haze episodes caused by vegetation and peat fires affect parts of Indonesia every year with significant impacts on human health and climate. The forest fires 1997/1998 were by far the largest in Indonesian history, burning between 5 and 8 million hectares before they were stopped by the monsoon rains in December 1997. Fires sprang up again in 1998 on Kalimantan when monsoon rain paused. Peat forests and peatlands are in particular severely affected. In the 1997/1998 haze event, 2.1-2.5 million hectare of peat swamp forest burnt in Indonesia. The remaining ash contains high concentrations of sulphur and sulphuric compounds which eventually leach into the groundwater, thus polluting groundwater and drinking water. The thicker the peat layer is and the higher the number of fires in the respective area the more sulphuric compounds will leach into the groundwater. Risk areas for the sulphur loads of the ash are identified. 相似文献
74.
75.
Umesh C. Chaube 《国际水资源开发杂志》1989,5(3):175-182
The plan for 3155 water projects is absolutely necessary for the socioeconomic development of the neglected Narmada basin. However, neither the 45‐year development target nor its cost (Rs 200 billion) is realistic. The environmental cost associated with the rehabilitation of 1.31 million oustees within the valley should be fully internalized in the development plan. In this article, submergence effects are estimated by extrapolation, and a socioeconomic and cultural profile of the oustees is presented. The feasibility of four possible resettlement alternatives is examined, keeping in view the objectives of rehabilitation and the performance of completed and ongoing projects. Guidelines are suggested for the preparation of a rehabilitation plan. 相似文献
76.
Shelley L. Miller Q.C. 《Risk Management & Insurance Review》2001,4(1):53-65
Tort reform of the motor accident insurance compensation scheme in the Australian state of New South Wales in 1999 came about as a result of an untested experiment in regulatory negotiation. This article is a first-hand account of the successful attempt to craft a consensual modification of the scheme through deliberations among a working group of service provider representatives. The author, a Canadian lawyer, investigated the prospects for change, acted as chief negotiator, and observed the legislative process that led to the final law reform. 相似文献
77.
Luis C. Nunes Paul Newbold Chung-Ming Kuan 《Oxford bulletin of economics and statistics》1997,59(4):435-448
Nelson and Plosser (1982), in a classic paper, failed to find strong evidence against the null hypothesis of a generating process with a unit autoregressive root for thirteen US macroeconomic time series. Perron (1989) claimed that such evidence was available for a majority of these series if the alternative hypothesis was of trend stationarity with a break in 1929. Zivot and Andrews (1992) treated the break date as endogenous, then finding strong evidence agcainst the null for a minority of these series. Our own analysis extends theirs by permitting a break under the null as well as the alternative hypothesis, and allowing for the sequential nature of the testing. Our empirical findings complete the circle. We find no strong evidence against the unit root hypothesis for any of the thirteen Nelson–Plosser series. 相似文献
78.
Employment Contacts and Minority-White Wage Differences 总被引:1,自引:0,他引:1
We study effects of job contacts on wages in inner-city Boston in 1989 and in the 1982 NLSY. Race/Hispanicity differences in wages are not explained by an absence of contacts among minority youths. Rather, in the Boston data, lower wages of black youths are explained by lower "returns" to their contacts. In the NLSY there is little evidence of lower return to black youths' contacts, but there is evidence of lower returns to Hispanic youths' contacts. 相似文献
79.
Large Non-Union Companies: How Do They Avoid a Catch 22? 总被引:1,自引:0,他引:1
Large non-union companies might be expected to enjoy extensive work-force flexibility deriving from their high-wage, high-involvement strategies. However, where there is a strong local union presence, this might be expected to exert a strong dampening effect on the levels of internal flexibility achieved. Such companies, fearful of union organization, could not then enjoy the freedoms that might be associated with a non-union strategy. Research conducted in the Republic of Ireland on large non-union US companies operating in the electronics industry suggests a conceptual framework indicating how a Catch-22 situation is avoided in these companies. 相似文献
80.
Heidi S.C.A. MuijenHeidi 《Journal of Business Ethics》2004,53(1-2):235-246
The author addresses the question of how to use value-learning processes to integrate corporate social responsibility (CSR) in organizations as an interesting challenge in (higher) education. Two strategies have been proposed for the issue of CSR: a compliance strategy and a cultural change strategy (Karssing, 2001). This article focuses on the ethical and philosophical presuppositions of these different approaches. The incorporation of CSR in organizations cannot be accomplished by means of a compliance strategy only. Rather, it needs to be supplemented by a strategy aimed at stimulating a transformation process on the corporate culture level. The perspective of change through dialogue is proposed as a means of innovating the curriculum and the primary processes of student education. This organizational change perspective is demonstrated by describing how (ethical) reflective aspects are integrated in the curriculum of the Free University of Amsterdam. An additional case study on organizational value learning is presented to illustrate the thesis that CSR presupposes that university is an adequate context where life-long learning begins. 相似文献