全文获取类型
收费全文 | 949篇 |
免费 | 81篇 |
国内免费 | 66篇 |
专业分类
安全科学 | 97篇 |
废物处理 | 9篇 |
环保管理 | 342篇 |
综合类 | 301篇 |
基础理论 | 112篇 |
环境理论 | 1篇 |
污染及防治 | 27篇 |
评价与监测 | 16篇 |
社会与环境 | 163篇 |
灾害及防治 | 28篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 33篇 |
2021年 | 29篇 |
2020年 | 35篇 |
2019年 | 33篇 |
2018年 | 36篇 |
2017年 | 59篇 |
2016年 | 66篇 |
2015年 | 43篇 |
2014年 | 31篇 |
2013年 | 75篇 |
2012年 | 58篇 |
2011年 | 68篇 |
2010年 | 29篇 |
2009年 | 38篇 |
2008年 | 29篇 |
2007年 | 46篇 |
2006年 | 40篇 |
2005年 | 33篇 |
2004年 | 37篇 |
2003年 | 25篇 |
2002年 | 35篇 |
2001年 | 21篇 |
2000年 | 19篇 |
1999年 | 25篇 |
1998年 | 17篇 |
1997年 | 18篇 |
1996年 | 19篇 |
1995年 | 15篇 |
1994年 | 10篇 |
1993年 | 5篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1973年 | 2篇 |
1972年 | 3篇 |
排序方式: 共有1096条查询结果,搜索用时 500 毫秒
741.
Addressing Declining Appropriations for Bureau of Reclamation Infrastructure: Policies Needed for Enabling Private Finance
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Martin W. Doyle 《Journal of the American Water Resources Association》2018,54(5):993-1000
Western water infrastructure was funded in the early and mid‐20th Century through federal financing through the Bureau of Reclamation. Over the past 30 years, federal financing has been less forthcoming, which has been commensurate with an increase in the need for financing rehabilitation and replacement of western irrigation infrastructure. As federal appropriations have declined, there has been increased interest in alternative approaches to infrastructure including public–private partnerships (P3s), loan guarantees, or title transfer of federal infrastructure. However, two of these approaches — P3s and loan guarantees — are precluded by existing federal budgetary policies, particularly Office of Management and Budget (OMB) scoring practices. If the OMB changed its policies for P3s or loan guarantees, private capital could play an important role in recapitalizing aging Reclamation infrastructure. 相似文献
742.
Qingling Shi 《Journal of Environmental Planning and Management》2019,62(5):797-817
Chinese governments play a key role in providing environmental public goods. Urban air quality is a significant indicator with which people evaluate the effects of governments’ environmental regulations and investments. This study aims to investigate how people's impression of government varies with air pollution in Chinese cities. Using the Baidu online search index on the specific keyword ‘corruption’ to represent public attitude toward the government, our estimations show that an increase in air pollution level yields a significant increase in online searches on this word. Such an effect is more significant on heavily polluted or severely polluted days. In further estimations, we find that people will not pay more attention to the polluters themselves on polluted days. These results are consistent with previous studies that air pollution causes people to be more depressed, selfish and sensitive to fairness. We conclude that efforts on air quality improvement will create a positive impression of government. 相似文献
743.
744.
Massimiliano Agovino Antonio Garofalo Angela Mariani 《Journal of Environmental Planning and Management》2018,61(9):1487-1510
Separate waste collection in Italy comes under the responsibility of local authorities, provinces, while national laws set quantitative targets to be achieved over time. Overall, just a few provinces have reached the thresholds set by the latest law (Legislative Decree 152/2006) and some territorial differentiation has been detected. The aim of this paper is twofold: to verify the effectiveness of Legislative Decree 152/2006 in promoting higher levels of separate collection and to test whether institutional quality (considering the following indicators: voice and accountability, regulatory quality, rule of law and corruption) affects provinces’ efficiency in the separate collection process. For this purpose, we implement the stochastic frontier analysis (SFA). Results suggest that the effectiveness of Legislative Decree 152/2006 has been affected by provinces’ institutional quality. In particular, the presence of institutional constraints did not allow the most virtuous provinces to achieve the targets set by law. 相似文献
745.
Pip Wallace Ross Martin Iain White 《Journal of Environmental Planning and Management》2018,61(7):1271-1288
This paper analyses regulatory responses to rapid intensification of the use of drones/remotely piloted aircraft (RPA) in the context of wildlife protection. Benefits and disadvantages of the technology to wildlife are examined, before three key limitations in policy and law are identified: failure to address wildlife disturbance in RPA regulation; reliance upon insufficiently comprehensive existing wildlife protection legislation to manage disturbance effects; and limited species-specific research on disturbance. A New Zealand case study further reveals an inconsistent regulatory approach struggling to keep pace with innovation, inadequate regulatory capture of environmental effects due to exemption as “aircraft”, and no recognition that specific geographical locations, such as coastal areas, distinguished by recreational pressures and high numbers of threatened species require special consideration. Recommendations include acknowledging the impact on wildlife in policy, gap analysis of legal arrangements for protection from disturbance (including airspace), and adoption of minimum approach distances to threatened species. 相似文献
746.
温度对水华微囊藻及孟氏浮游蓝丝藻生长、光合作用及浮力变化的影响 总被引:11,自引:1,他引:10
通过批量培养实验,测定培养过程中藻的生物量、光合放氧速率及浮力等的变化,研究了2种典型水华蓝藻-水华微囊藻及孟氏浮游蓝丝藻在不同温度下的生长和光合作用特征及浮力调控的机制结果表明,水华微囊藻在温度低于13℃时几乎不能生长,高于16℃能缓慢生长,且随着温度升高,生长速率增大;孟氏浮游蓝丝藻在温度为10℃时就能缓慢生长,当温度高于16℃时即能够较好生长;2种藻的生长速率在10~28℃范围内都随温度升高而增大.2种蓝藻在10℃以上均能进行光合作用,且在实验温度范围内(10~28℃)随温度的升高而增强当温度从28℃转至13℃以下温度培养时,2种蓝藻的浮力下降明显,细胞内伪空胞、糖及蛋白质的变化表明,糖的积累使细胞密度增大是细胞浮力下降的主要原因;在72h之内,水华微囊藻和浮游蓝丝藻细胞内糖含量分别增加了2.2倍和2.5倍,这说明温度降低至13℃以下,水华微囊藻下沉趋于休眠,而孟氏游浮蓝丝藻则趋于底栖继续生长;温度升高至13℃以上,水华微囊藻趋于复苏和上浮,而孟氏浮游蓝丝藻趋于浮游. 相似文献
747.
青霉木质纤维素降解酶系研究进展 总被引:2,自引:0,他引:2
越来越多的研究表明青霉属(Penicillium)真菌中的一些种类不仅能分泌组成齐全、酶活较高的木质纤维素降解酶系,而且具有易培养和生长快的优势.本文就国内外对青霉菌木质纤维素降解酶系研究的最新动态进行了综述,包括菌株的选育、纤维素酶系的特性与合成调控,以及基因分析与克隆.同时介绍了斜卧青霉纤维素酶系的生产与发酵工艺,以及酶解过程分析等相关研究进展.表4参48 相似文献
748.
749.
环境监测是一项政府行为,如何在社会主义市场经济条件下,正确处理“政府行为”与市场经济的矛盾,已成为各级环保部门共同探讨的、需要妥善解决的问题。因此,根据经济学的有关理论,对环境监测这一领域在社会主义市场经济中所处的地位、作用作了全面论述,并对理解环境监测的“政府行为”提出看法和见解。 相似文献
750.
The paper presents a partial classification of safety rules as constraints imposed from outside on the freedom of choice of individuals or companies. The classification is linked to the Reason model of skill-, rule-, and knowledge-based behaviour. The imposition of constraints is related to a number of criteria concerning the context and use of the rules to arrive at proposals for when and where to apply what type of rule. To illustrate the principles discussed an example is given of the rule from the Dutch Working Environment legislation concerning the requirement to use “current state of the art in prevention” in companies. The paper proposes providing procedural rule support to companies on how to meet the rule, in the form of a data bank of practicable solutions to health and safety problems. 相似文献