全文获取类型
收费全文 | 9331篇 |
免费 | 730篇 |
国内免费 | 551篇 |
专业分类
安全科学 | 1867篇 |
废物处理 | 193篇 |
环保管理 | 3267篇 |
综合类 | 2871篇 |
基础理论 | 970篇 |
环境理论 | 10篇 |
污染及防治 | 308篇 |
评价与监测 | 372篇 |
社会与环境 | 378篇 |
灾害及防治 | 376篇 |
出版年
2023年 | 110篇 |
2022年 | 156篇 |
2021年 | 228篇 |
2020年 | 297篇 |
2019年 | 236篇 |
2018年 | 209篇 |
2017年 | 258篇 |
2016年 | 356篇 |
2015年 | 322篇 |
2014年 | 385篇 |
2013年 | 540篇 |
2012年 | 551篇 |
2011年 | 674篇 |
2010年 | 465篇 |
2009年 | 579篇 |
2008年 | 415篇 |
2007年 | 559篇 |
2006年 | 548篇 |
2005年 | 436篇 |
2004年 | 455篇 |
2003年 | 349篇 |
2002年 | 321篇 |
2001年 | 311篇 |
2000年 | 311篇 |
1999年 | 236篇 |
1998年 | 161篇 |
1997年 | 162篇 |
1996年 | 137篇 |
1995年 | 134篇 |
1994年 | 65篇 |
1993年 | 74篇 |
1992年 | 66篇 |
1991年 | 53篇 |
1990年 | 34篇 |
1989年 | 28篇 |
1988年 | 38篇 |
1987年 | 35篇 |
1986年 | 27篇 |
1985年 | 23篇 |
1984年 | 29篇 |
1983年 | 17篇 |
1982年 | 22篇 |
1981年 | 18篇 |
1980年 | 24篇 |
1979年 | 34篇 |
1978年 | 21篇 |
1975年 | 14篇 |
1973年 | 14篇 |
1972年 | 16篇 |
1971年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
261.
262.
高校内部审计存在的问题与对策的初步探讨 总被引:1,自引:0,他引:1
田静敏 《中国环境管理干部学院学报》2004,14(2):107-109
目前高校内部经济活动发生了很大变化,内部的经济管理也变得更加复杂。如何有效的保证教育资金合理运用,保证内部经济活动健康、有序的开展,教育审计有着举足轻重的作用。本文分析了高校内部审计存在的问题,初步探讨解决的对策。 相似文献
263.
流域管理:权力产权的外部性问题 总被引:3,自引:0,他引:3
水资源的自然、经济和社会属性要求政府对流域的开发和利用进行管理,以解决个体使用者的外部性问题.但实际上由于政府并不是只有单一目标的统一组织,在分权体制下,不同区域、部门的政府单元掌握着实际权力.由于权力也存在外部性,各管理区域、部门之间存在利益冲突,导致政府的管理失效.解决政府权力外部性的办法:一是要转变政府职能,改变政府的激励机制;二是严格界定各政府单元的权力界限,对流域进行统一管理. 相似文献
264.
265.
Best management practices compliance monitoring approaches for forestry in the eastern United States
Many of the eastern states that have published best management practices (BMPs) or forest management guidelines have also developed compliance monitoring programs to assess the application of these BMPs or guidelines on public and private forest land. The approaches among these states to collecting on-site monitoring data (measuring compliance) and evaluating sites are variable. A survey of eastern states found that almost all southern states monitor application of BMPs, but proportionally fewer of the northern states have established compliance monitoring programs. The state forestry agencies provide the leadership for these programs in most of the eastern states. States that monitor tend to evaluate all public and private forest landowner categories located within their states. In general, northern states monitor a broader array of site resources (e.g., cultural resources, visual quality) as compared to southern states which focus on water quality and wetlands protection. However, northern states focus their monitoring on timber harvesting, forest road construction and maintenance as compared to southern states which tend to monitor a broader array of forest management activities (e.g., site preparation, reforestation). When selecting sites for monitoring, the most common approach is to select some sites from all landowner categories within the state. Many states do not specify any criteria to identify sites for monitoring so that all sites have an equal chance for selection. Some states do use specific criteria to filter sites for monitoring, most commonly size of forest management activity and proximity to water. 相似文献
266.
Andrew J. Londo 《Water, Air, & Soil Pollution: Focus》2004,4(1):235-243
This study examined the knowledge levels of Mississippi Non Industrial Private Forest (NIPF) landowners. Data were collected by passing out surveys to participants in Best Management Practices (BMP) educational programs held in conjunction with County Forestry Association (CFA) meetings across Mississippi. Ten CFA's participated in this study. Educational program participants were asked to fill out a survey with several demographic and BMP questions prior to the educational program. Results show that BMP program participants owned an average of 113 hectares, whereas the average Mississippi NIPF landowner owns 20 hectares. Responses to BMP related questions show that Mississippi NIPF landowners have a low level of knowledge concerning BMP's. This situation is likely similar to other states in the Southeastern United States. It can be assumed that county forestry association members are more active and informed about managing their forest land. Therefore, these results may overestimate the BMP knowledge level all landowners in Mississippi.Improved educational programs for NIPF landowners, along with better communication between foresters, loggers, and NIPF landowners are needed if BMP's are to be implemented effectively in Mississippi and across the southern region. 相似文献
267.
268.
钻井是石油天然气勘探开发过程中的重要环节,钻井过程中污染物的排放管理也受到各国普遍的重视。对钻井污染物的特点进行了分析,在此基础上概括地介绍了美国的相关环境管理法规体系。重点论述了与钻井排污有关的资源保护与补偿法、安全饮用水法、清洁水法等,总结了可供我国借鉴的若干法规、标准制定的理念和方法。 相似文献
269.
270.
Forest resources play a key role and provide many basic needs to communities in developing economies. To assess the patterns of vegetation cover change, as a corollary of resource utilization, satellite imagery, ground truth data, and image processing techniques can be useful. This article is concerned with identifying change in major vegetation types in East Timor between 1989 and 1999, using Landsat Thematic Mapper data. The results highlight a significant level of deforestation and decline in foliage cover. All major vegetation cover types declined from 1989 to 1999, and there was a sizeable increase in degraded woodlands. This decline has had considerable impact on the livelihoods of rural and urban communities. Causes for these changes include: economic exploitation of abundant resources; and implications of transmigration policies implemented during Indonesian rule, resulting in increased competition for land and woodland resources. As the new nation of Timor‐Leste establishes itself, it must consider its current stock and distribution of natural capital to ensure that development efforts are geared towards sustainable outcomes. Without the knowledge of historical patterns of resource consumption, development efforts may, unwittingly, lead to continuing decline in forest resources. 相似文献