全文获取类型
收费全文 | 6242篇 |
免费 | 777篇 |
国内免费 | 297篇 |
专业分类
安全科学 | 1230篇 |
废物处理 | 75篇 |
环保管理 | 1640篇 |
综合类 | 2243篇 |
基础理论 | 759篇 |
环境理论 | 44篇 |
污染及防治 | 206篇 |
评价与监测 | 288篇 |
社会与环境 | 520篇 |
灾害及防治 | 311篇 |
出版年
2024年 | 138篇 |
2023年 | 202篇 |
2022年 | 178篇 |
2021年 | 263篇 |
2020年 | 269篇 |
2019年 | 264篇 |
2018年 | 220篇 |
2017年 | 355篇 |
2016年 | 319篇 |
2015年 | 270篇 |
2014年 | 266篇 |
2013年 | 370篇 |
2012年 | 486篇 |
2011年 | 496篇 |
2010年 | 336篇 |
2009年 | 324篇 |
2008年 | 242篇 |
2007年 | 293篇 |
2006年 | 318篇 |
2005年 | 256篇 |
2004年 | 191篇 |
2003年 | 169篇 |
2002年 | 141篇 |
2001年 | 123篇 |
2000年 | 121篇 |
1999年 | 97篇 |
1998年 | 80篇 |
1997年 | 60篇 |
1996年 | 69篇 |
1995年 | 67篇 |
1994年 | 39篇 |
1993年 | 44篇 |
1992年 | 35篇 |
1991年 | 23篇 |
1990年 | 20篇 |
1989年 | 19篇 |
1988年 | 12篇 |
1987年 | 12篇 |
1986年 | 13篇 |
1985年 | 20篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1973年 | 7篇 |
1972年 | 7篇 |
排序方式: 共有7316条查询结果,搜索用时 15 毫秒
1.
2.
Performance evaluation of Health, Safety and Environment (HSE) is the measurement of a company's achievement in HSE management. In order to receive a comprehensive and objective evaluation result, it is necessary to consider all evaluation factors and experts at different levels when HSE performance assessment is conducted. To improve conventional HSE performance evaluation, where weighted average method was used, a Fuzzy Comprehensive Evaluation (FCE) method is used in this study by taking experts' weights into account. Further, an HSE operating performance assessment system is designed to simplify manual and complex assessment process and generate charts and analysis reports automatically. Finally, a case of petrochemical enterprise is used to illustrate the effectiveness of the method and system. 相似文献
3.
西藏自治区土地资源的适宜性评价与利用 总被引:4,自引:0,他引:4
本文综合评价了西藏自治区土地资源的适宜性及其质量.阐明了影响土地资源潜力发挥的主要限制因素,分析了土地资源利用现状、存在问题和开发潜力。并在此基础上、提出了西藏自治区土地资源合理开发利用的方向、对策和措施。 相似文献
4.
Robert B. Olshansky 《Environmental management》1996,20(1):11-23
The California Environmental Quality Act (CEQA) has evolved from a mini-NEPA, first enacted in 1970, into a procedural act
that affects the approval process of all large developments in California. In 1990, California local governments produced
over 1600 environmental impact reports and 30,000 initial studies under CEQA. Because of its widespread use, CEQA has periodically
drawn the attention of the state legislature, most recently in 1993, when over 60 CEQA reform bills were introduced. This
paper describes the CEQA process and evaluates its success at meeting its explicit and implicit goals. The research includes
a statewide survey of CEQA practice, sent to the planning departments of all 513 local governments in California in 1991.
Survey respondents agreed that CEQA helps in evaluating environmental impacts, reducing impacts, informing the public, and
coordinating public agency review. It is effective in reducing the environmental impacts of individual projects, but is not
as effective in improving environmental quality on an areawide scale. This research concludes that CEQA has led to positive
outcomes and is not as deeply flawed as many of its critics claim. Still, CEQA as currently designed may not be the optimal
vehicle for ensuring environmental quality. 相似文献
5.
Donna M. Cosgrove Gary S. Johnson 《Journal of the American Water Resources Association》2004,40(6):1469-1482
ABSTRACT: Increasing demands on western water are causing a mounting need for the conjunctive management of surface water and ground water resources. Under western water law, the senior water rights holder has priority over the junior water rights holder in times of water shortage. Water managers have been reluctant to conjunctively manage surface water and ground water resources because of the difficulty of quantification of the impacts to surface water resources from ground water stresses. Impacts from ground water use can take years to propagate through an aquifer system. Prediction of the degree of impact to surface water resources over time and the spatial distribution of impacts is very difficult. Response functions mathematically describe the relationship between a unit ground water stress applied at a specific location and stream depletion or aquifer water level change elsewhere in the system. Response functions can be used to help quantify the spatial and temporal impacts to surface water resources caused by ground water pumping. This paper describes the theory of response functions and presents an application of transient response functions in the Snake River Plain, Idaho. Transient response functions can be used to facilitate the conjunctive management of surface and ground water not only in the eastern Snake River Plain basin, but also in similar basins throughout the western United States. 相似文献
6.
介绍了如何在国家级生态示范区的可持续发展评估中运用灰色系统理论构建定量评估系统模型,并给出了关系型指标表、量纲模型、多元灰色预测模型和发展系数模型以及应用实例.根据该评估系统模型所开发的灰色评估系统由数学模型、计算机软件和硬件组成,可自动完成量纲统一、指标预测、相关分析、综合评估和趋势图表的运算和输出. 相似文献
7.
水稻生产气象灾害危险性分析:—以湖南省常德市水稻生产为例 总被引:2,自引:0,他引:2
本文通过对研究区水稻气象灾害规律的研究和危险性评价,计算了不同等级的水稻综合风险率,为保险部门制定水稻保险费率提供了科学依据. 相似文献
8.
Impacts on industry of Europe's emerging chemicals policy REACh 总被引:1,自引:0,他引:1
For Europe, a new regime in chemicals regulation is about to start. After the proposal of the European Commission concerning the Registration, Evaluation and Authorization of Chemicals (REACh) passed its readings in the European Parliament and some differences with the European Council of Ministers were resolved, the regulation will come into force in June 2007. This paper is focused on the question how serious the cost burdens for industry induced by REACh will be, and whether the New European Member States (NMS) which joined the European Union in May 2004 will be able to cope with the regulation. This evaluation has been done by assessing the legislative, administrative and economic framework in New Member States and by analysing real business cases in companies. The empirical showcase business impact studies are at the same time of interest for companies of EU-15 states, other European countries who may implement the regulation, and even for exporters of raw materials and chemicals outside Europe, who will also have to comply with REACh if they market in the European Community. The results give no indications that REACh adoption will bring significant drawbacks to companies in the NMS. The emerging regulation will bring challenges for individual companies, especially for small and medium-sized ones, but for the European chemical industry as a whole, there is no question that it will be able to cope with REACh burdens without losing its global competitiveness. 相似文献
9.
10.
设计了一种新型双室空气阴极微生物燃料电池(MFC)并将其作为生物传感器,与传统双室空气阴极MFC进行对比,考察其电化学性能及用于快速检测BOD的性能。结果表明:新型空气阴极MFC可有效提高功率密度并降低内阻,其功率密度最高为897 mW·m−2,而内阻最低为92 Ω;该MFC可用于直接快速检测高浓度有机物的BOD,对醋酸钠底物的线性检测限为1 280 mg·L−1,在此底物浓度下MFC的检测时间为31.2~66 h,线性可决系数R2为0.97~0.99;对于GGA底物的线性检测限为1 250 mg·L−1,在此底物浓度下MFC的检测时间为33~67 h,线性可决系数R2为0.98。本研究可为MFC型BOD检测传感器的性能优化提供参考。 相似文献