全文获取类型
收费全文 | 4598篇 |
免费 | 416篇 |
国内免费 | 139篇 |
专业分类
财政金融 | 103篇 |
工业经济 | 173篇 |
计划管理 | 589篇 |
经济学 | 684篇 |
综合类 | 389篇 |
运输经济 | 31篇 |
旅游经济 | 48篇 |
贸易经济 | 281篇 |
农业经济 | 332篇 |
经济概况 | 317篇 |
水利工程 | 2206篇 |
出版年
2024年 | 20篇 |
2023年 | 55篇 |
2022年 | 111篇 |
2021年 | 161篇 |
2020年 | 135篇 |
2019年 | 157篇 |
2018年 | 102篇 |
2017年 | 160篇 |
2016年 | 167篇 |
2015年 | 207篇 |
2014年 | 336篇 |
2013年 | 300篇 |
2012年 | 365篇 |
2011年 | 405篇 |
2010年 | 304篇 |
2009年 | 267篇 |
2008年 | 282篇 |
2007年 | 286篇 |
2006年 | 274篇 |
2005年 | 236篇 |
2004年 | 152篇 |
2003年 | 131篇 |
2002年 | 108篇 |
2001年 | 95篇 |
2000年 | 69篇 |
1999年 | 50篇 |
1998年 | 41篇 |
1997年 | 37篇 |
1996年 | 43篇 |
1995年 | 22篇 |
1994年 | 25篇 |
1993年 | 10篇 |
1992年 | 15篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 5篇 |
排序方式: 共有5153条查询结果,搜索用时 0 毫秒
1.
《Socio》2021
Haze pollution has become a new threat to China's sustainable development, but it may be that local government behaviour can play an important role in the prevention and control of pollutants. A dynamic spatial autoregressive (SAR) model is used to study the relationship between local government competition and haze pollution. To further explore the indirect impact of factor market distortion on haze pollution and control potential endogeneity problems, a newly developed intermediary effect model that incorporates the characteristics of the generalized method of moments (GMM) is utilized to explore how factor market distortion indirectly affects haze pollution. The research results show that regional haze pollution in China is characterized by significant spatial correlation, and local government competition has a positive impact on haze pollution; that is, local government competition exacerbates haze pollution. In general, local government competition not only directly leads to an increase in haze pollution but also further intensifies it by distorting the local factor market, and the intermediary role of factor market distortion is approximately 7.04%. The results of the regional inspection found that competition among local governments in the eastern region did not lead to haze pollution, and distortion of the factor market did not exist as an intermediary effect. However, both direct and intermediary effects are significant in the central and western regions. Therefore, an official performance appraisal system that includes ecological constraints should be established to guide the benign transformation of local government competition, and an environmental management mechanism must be developed for joint prevention and control to reduce haze pollution. In addition, the free flow of factors and marketization are equally important. 相似文献
2.
This study develops the AIEDA tourism advertising effects model and examines this model by tourism destination types and advertising formats in a field experiment. The AIEDA model extends the traditional AIDA model in the advertising field and additionally considers the unique features of tourism products. It includes five hierarchical stages: Attention→ Interest→Evaluation (Perceived Usefulness→ Perceived Credibility) → Desire →Action. Findings of experimental research indicate that destination type and advertising format have main effects and interaction effects on tourism advertising effects. In addition, this study discovered that, for natural and cultural destinations, video ads yielded similar or more positive advertising effects than virtual reality ads, whereas print was the least effective advertising format. 相似文献
3.
《Socio》2021
Based on the day-night PM2.5 difference of the nearest atmospheric monitoring points to measure whether there is illegal emission, this paper explores the impact of environmental protection officials' tenure (EPLT) on illegal emissions. The results show that there is a positive correlation between EPLT and illegal emissions. Stable EPLT can reduce illegal emissions by increasing environmental information disclosure and environmental subsidies. It can increase illegal emissions by weakening public pollution reporting and media supervision, environmental law enforcement and promoting corruption. In addition, EPLT can increase illegal emissions as EPLT is less than 3.55 years, while EPLT can increase illegal emissions as EPLT exceeds 6.21 years. Further, when mayor's tenure and EPLT are both stable, the promotion effect of EPLT on illegal emission is stronger. Stable company director's tenure can also aggravate the promotion effect of EPLT on illegal emissions. 相似文献
4.
Lake Chivero: A management case study 总被引:1,自引:0,他引:1
C. H. D. Magadza 《Lakes & Reservoirs: Research and Management》2003,8(2):69-81
Lake Chivero in Zimbabwe was shown to be hypereutrophic. Historical data showed that the eutrophication process had been arrested in the late 1970s. However, a combination of poor planning, multiplicity of jurisdiction, mismatch between rate of urbanization and waste management investment, recent changes in the local climate and a permissive, immature political system that called for no public accountability resulted in environmental management breakdown leading to hypereutrophication of the lake. The case of Lake Chivero is presented as an example of a wider global issue regarding the status of environmental management in competition with other priorities in emerging democracies. 相似文献
5.
6.
7.
This article specifies what an optimal pollution tax should be when dealing with a vertical Cournot oligopoly. Polluting firms
sell final goods to consumers and outsource their abatement activities to an environment industry. It is assumed that both
markets are imperfectly competitive. Thus, the tax is a single instrument used to regulate three sorts of distortions, one
negative externality and two restrictions in production. Consequently, the optimal tax rate is the result of a trade-off that
depends on the firms’ market power along the vertical structure. A detailed analysis of Cournot-Nash equilibria in both markets
is also performed. In this context, the efficiency of abatement activities plays a key-role. It gives a new understanding
to the necessary conditions for the emergence of an eco-industrial sector.
相似文献
8.
珠江口门海堤堤型的选择 总被引:2,自引:0,他引:2
珠江口站地区面临南海、大陆岸线长457km,遭受洪水。潮汐、台风的影响,河口滩涂 发育迅速,以约100m/a的速度向大海延伸。随着沿海地区的经济发展,滨海-2m高程以上的滩涂的4万hm^2正在和将要建堤围垦和开发利用,原有海堤也亟待加固提高,因此,对珠江口门坝有海堤堤型资料进行收集、整理,分析总结,选择经济可行的海堤堤型,具有重要的现实意义。文中收集了珠江口门的几种主要堤型,通过对各种堤基工程地质 相似文献
9.
Baak K. Taeli 《Lakes & Reservoirs: Research and Management》2006,11(3):149-168
Lake Mogan, located in the steppes of central Anatolia, is a vital Turkish ecological system, in terms of its water resources, flora and fauna. The lake also is a unique recreational area for Ankara, the capital of Turkey. However, the lake is currently threatened by severe pollution, being under the risk of serious degradation because of (i) uncontrolled urbanization; (ii) point and non‐point source pollution; (iii) inefficient sewerage systems; (iv) sediment transportation and pollution via influent creeks to the lake; (v) uncontrolled soil erosion in its drainage basin; (vi) inappropriate flood control measures; and (vii) severe degradation of the natural wetlands within its drainage basin. This study evaluates the influence of its influent creeks on the water quality of Lake Mogan, mainly because the creeks are believed to be responsible for the major pollutant load reaching the lake, and because the extensive database documenting this situation has not previously been critically evaluated. Accordingly, this study reviews (i) change in the water quality of Lake Mogan between 1993 and 2002; (ii) the water quality classification of the major influent creeks feeding Lake Mogan; and (iii) the influence of the influent creeks on the water quality of the lake between 1993 and 2004. 相似文献
10.
水生生物环境诊断(AOD)技术应用研究 总被引:4,自引:0,他引:4
介绍一种新型的毒性试验方法——水生生物环境诊断(AOD)技术,该方法将冷冻浓缩和生物测试技术有机地相结合,较好地解决了低毒性水体的毒性测试问题。应用本项技术以红鳍鱼为受试生物,分别对湖北武汉马伧湖、墨水湖、广东深圳河、长江干流寸滩等几个断面、丹江口水库白河、丹江河口、老灌河等不同水体进行AOD测试,所得48hr-LC\-50结果与实际水质状况基本相符。 相似文献