全文获取类型
收费全文 | 541篇 |
免费 | 31篇 |
国内免费 | 29篇 |
专业分类
安全科学 | 32篇 |
废物处理 | 2篇 |
环保管理 | 249篇 |
综合类 | 129篇 |
基础理论 | 82篇 |
污染及防治 | 26篇 |
评价与监测 | 39篇 |
社会与环境 | 32篇 |
灾害及防治 | 10篇 |
出版年
2024年 | 3篇 |
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 14篇 |
2020年 | 15篇 |
2019年 | 12篇 |
2018年 | 14篇 |
2017年 | 18篇 |
2016年 | 20篇 |
2015年 | 13篇 |
2014年 | 22篇 |
2013年 | 30篇 |
2012年 | 22篇 |
2011年 | 39篇 |
2010年 | 25篇 |
2009年 | 39篇 |
2008年 | 39篇 |
2007年 | 41篇 |
2006年 | 25篇 |
2005年 | 11篇 |
2004年 | 14篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 11篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 10篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 8篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1973年 | 1篇 |
排序方式: 共有601条查询结果,搜索用时 193 毫秒
481.
环境监测站实施国家室认可的可行性探讨 总被引:3,自引:0,他引:3
介绍了国家实验室认可机构的建立,资质以及国家实验室认可准则的依据等概况。阐述了各级环境监测站在环境监测中实施ISO标准的必要性,实施国家实验室认可的可行性,以及相应的操作流程,简略评述了实施国家实验室认可对环境监测站的作用。 相似文献
482.
There is an increasing interest in the quality of soil, especially for small geographical areas. We present a method to estimate the percent of the area in a county or hydrological basin that is eroded. There are sample data (for several counties in eastern Iowa) from the National Resources Inventory and population data on land use, land capability class, rainfall and slope length and steepness. Using the Gibbs sampler we perform Bayesian predictive inference to obtain estimates for the non-sampled units. These estimates, together with the sample data, provide an estimate of the proportion of the total area that is eroded. We assess the quality of fit of our model using two cross-validation exercises and graphical methods. 相似文献
483.
Mary Lou Thompson Lawrence H. Cox Paul D. Sampson David C. Caccia 《Environmental and Ecological Statistics》2002,9(4):321-339
Environmental regulatory standards are intended to protect human health and environmental welfare. Current standards are based on scientific and policy considerations but appear to lack rigorous statistical foundations and may have unintended regulatory consequences. We examine current and proposed U.S. environmental regulatory standards for ozone from the standpoint of their formulation and performance within a statistical hypothesis testing framework. We illustrate that the standards can be regarded as representing constraints on a percentile of the ozone distribution, where the percentile involved depends on the defined length of ozone season and the constraint is stricter in regions with greater variability. A hypothesis testing framework allows consideration of error rates (probability of false declaration of violation and compliance) and we show that the existing statistics on which the standards are based can be improved upon in terms of bias and variance. Our analyses also raise issues relating to network design and the possibilities of defining a regionally based standard that acknowledges and accounts for spatial and temporal variability in the ozone distribution. 相似文献
484.
485.
Cleanup standards at hazardous waste sites include (i) numeric standards (often risk-based), (ii) background standards in which the remediated site is compared with data from a supposedly clean region, and (iii) interim standards in which the remediated site is compared with preremediation data from the same site. The latter are especially appropriate for verifying progress when an innovative, but unproven, technology is used for remediation. Standards of type (i) require one-sample statistical tests, while those of type (ii) and type (iii) call for two-sample tests. This paper considers two-sample tests with an emphasis upon the type (iii) scenario. Both parametric (likelihood ratio) and nonparametric (linear rank) protocols are examined. The methods are illustrated with preremediation data from a site on the National Priorities List. The results indicate that nonparametric procedures can be quite competitive (in terms of power) with distributional modelling provided a near optimal rank test is selected. Suggestions are given for identifying such rank tests. The results also confirm the importance of sound baseline sampling; no amount of post-remediation sampling can overcome baseline deficiencies.This paper has been prepared with partial support from the United States Environmental Protection Agency under a Cooperative Agreement Number CR-815273. The contents have not been subject to Agency review and therefore do not necessarily reflect the views or policies of the Agency and no official endorsement should be inferred. 相似文献
486.
487.
工业生态学的演化与原理 总被引:4,自引:0,他引:4
在总结当前工业生态学(IE)主要研究成果的基础上,分析了IE的演化进程,阐述了IE的原理,并展望了研究方向。指出:IE是一门以提高工业过程中原料使用效率、降低废物排放弃为目的,研究工业系统及其与环境之间相互关系的应用生态学;其化过程经历了孕育、萌芽的提出第三个阶段;其主要研究对象是工业生态系统,而工业生态系统的主体是工业生产部门;工业生态系统的功能主要表现在工业生产过程中的物流、能流和信息流三个方面。 相似文献
488.
489.
就大气环境影响评价中理解和执行GB/T13201-91、GB3095-82的几个问题提出了看法和建议。 相似文献
490.
Evaluation model for developing,implementing, and assessing conservation education programs: Examples from Belize and Costa Rica 总被引:1,自引:0,他引:1
Susan K. Jacobson 《Environmental management》1991,15(2):143-150
Evaluation of conservation education programs can: (1) provide accountability in demonstrating a program's worth, (2) offer
an opportunity for receiving feedback and improving programs, (3) further our understanding of the process of program development,
and (4) promote conservation education by substantiating claims about its benefits. The Planning-Process-Product systems evaluation
model provides feedback needed for making decisions about the development, implementation, and outcome of a program. Planning
evaluation was useful in assessing the needs, goals, opportunities, and constraints of a number of programs in Costa Rica
and Belize, such as a forestry education project and a zoo outreach program. It provided a basis for making planning decisions
incorporating specific objectives, such as the reforestation of a region or a change in knowledge and attitudes in program
participants. Process evaluation provided a Costa Rican sustainable development program with feedback during its implementation
and enabled it to modify and improve its newsletter for local farmers and its ecology classes for school children. Product
evaluation assessed project accomplishments, such as the $700,000 raised by the Children's Rainforest group and the 20 miles
of riparian land under conservation management as part of the Belize Community Baboon Sanctuary project. Outcomes are compared
with the programs original monetary or land management objectives to determine the success of the programs and to provide
feedback for improvement. 相似文献