全文获取类型
收费全文 | 623篇 |
免费 | 44篇 |
国内免费 | 18篇 |
专业分类
安全科学 | 24篇 |
废物处理 | 4篇 |
环保管理 | 122篇 |
综合类 | 186篇 |
基础理论 | 209篇 |
环境理论 | 1篇 |
污染及防治 | 15篇 |
评价与监测 | 29篇 |
社会与环境 | 82篇 |
灾害及防治 | 13篇 |
出版年
2023年 | 8篇 |
2022年 | 10篇 |
2021年 | 19篇 |
2020年 | 16篇 |
2019年 | 11篇 |
2018年 | 10篇 |
2017年 | 19篇 |
2016年 | 19篇 |
2015年 | 18篇 |
2014年 | 18篇 |
2013年 | 40篇 |
2012年 | 29篇 |
2011年 | 37篇 |
2010年 | 38篇 |
2009年 | 33篇 |
2008年 | 35篇 |
2007年 | 45篇 |
2006年 | 36篇 |
2005年 | 45篇 |
2004年 | 30篇 |
2003年 | 23篇 |
2002年 | 21篇 |
2001年 | 18篇 |
2000年 | 25篇 |
1999年 | 13篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1996年 | 6篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有685条查询结果,搜索用时 15 毫秒
81.
82.
Interactions between water and land in The Netherlands 总被引:1,自引:0,他引:1
The Netherlands are one of the most densely populated coastal countries in the world and there is only limited space for living,
working, transport and recreation, while there is also the need to preserve and expand valuable natural habitats. In order
to solve many existing and future conflicts of interest, and in order to create ‘added value’, strategies are developed to
optimize the use of water-land systems.
The principle of ‘building with nature’ is applied in order to integrate land in sea and water in land in such a way that
future generations will be able to use coastal resources in a sustainable way, including a minimal effort to maintain the
coastline and the promotion of a multiple-use system.
The concept of Integrated multifunctional sustainable coastal zone development is introduced. This concept deals with a balanced
approach to the lack of space for present and future coastal uses in relation to each other, to the hinterland, and to the
sea. Flexible master plans are developed, taking into account many functions of the coastal zone, and facilitating adaptation
to future developments—e.g. impacts of climate change and relative sea level rise. In this regard increasing the flexibility
of the coastal zone is of vital importance.
Large-scale coastal land reclamations in The Netherlands are dealt with, based on two different principles: (1) polder systems
(low lying land reclamations surrounded and protected by dikes), (2) systems of ‘building with nature’—land reclamation protected
by man-made foreshores, beaches and dunes. In the latter type new flexible dynamic-equilibrium coasts are created for many
functions, while coastal vulnerability is reduced and a flexible coast is developed. 相似文献
83.
西鄂尔多斯国家级自然保护区旅游开发的战略意义及可行性分析 总被引:2,自引:0,他引:2
西鄂尔多斯自然保护区是一个以保护古老残遗植物及草原向荒漠过渡的植被带和多样的生态系统为主要对象的综合性自然保护区。受传统资源开发模式的影响,生态环境十分脆弱,保护难度极大。西部大开发为这一区域旅游开发提供了机遇,通过旅游开发,建立新的经济开发模式,促使区域生态环境好转,以促进保护区的建设和发展。本文就该区域旅游开发的战略意义和可行性进行了探讨。 相似文献
84.
Kristina?D.?RothleyEmail author Charlene?Rae 《Environmental Modeling and Assessment》2005,10(2):107-113
In this paper we apply graph theory in a reserve selection exercise to explore the tradeoffs between maintaining connectivity and minimizing the total area of a protected area network. Rather than focus on a single organism, we used a multi-species approach and looked at the tradeoff curves for organisms with varying dispersal abilities. We first generated the tradeoff curves using a graph-based metric to determine the importance of individual patches for maintaining connectivity. We then performed an analogous set of analyses using patch size as a surrogate measure of importance. 相似文献
85.
Darek J. Nalle Jeffrey L. Arthur Claire A. Montgomery John Sessions 《Environmental Modeling and Assessment》2002,7(2):99-105
An optimization model for land reservation was developed that explicitly selects parcels in the most compact or contiguous manner possible while meeting habitat requirements and a budget limitation. The model was used to compare the effects of an existing reserve network on future parcel spatial locations and total cost. Using habitat and land value data from Josephine County, Oregon, it was found that a system of existing reserves created by various policies and overseen by different agencies can decrease future reserve compactness and contiguity, and increase total cost. This work suggests that coordinated planning can result in more efficient conservation efforts for less cost. 相似文献
86.
87.
The Effect of Incremental Reserve Design and Changing Reservation Goals on the Long-Term Efficiency of Reserve Systems 总被引:4,自引:0,他引:4
Abstract: Selecting reserve areas based on percentages, such as 10% or 12% of a bioregion, is common in conservation planning despite widespread admission that such percentages are arbitrary and likely to be inadequate for the conservation of all biodiversity. Reserve systems based on these relatively low percentage targets are likely to require expansion in the future, resulting in the assembly of reserve systems over many years (incremental reserve design). How then will incremental reserve design, such as increasing percentage targets over time, affect the long-term efficiency of marine reserve systems? We used South Australia as a case study to investigate how changing percentage targets affects the contribution of individual planning units to efficient reserve design. Selection frequency counts provided a measure of a planning unit's conservation value. For the majority of planning units, changing targets led to a change in their conservation value indicating, for example, that planning units identified as high-value sites at a low-percentage conservation target may be of lesser importance when targets are increased. Despite the variability in the value of individual planning units at different targets, there was no loss in efficiency from incremental design of reserve systems based on systematic methods compared with purpose-built reserve systems (i.e., the system is assembled in a single iteration). The exception was when incrementally designed systems were based on South Australia's existing marine reserve system—a system developed in an ad hoc method. The result was reserve systems that were less efficient, less compact, and larger in size. This suggests that systematic approaches have an important role for efficient reserve design when there is uncertainty about the target level of reservation . 相似文献
88.
Abstract: The Iberian Peninsula harbors about 50% of European plant and terrestrial vertebrate species and more than 30% of European endemic species. Despite the global recognition of its importance, the selection of protected areas has been ad hoc and the effectiveness of such choices has rarely been assessed. We compiled the most comprehensive distributional data set of Iberian terrestrial plant and vertebrate species available to date and used it to assess the degree of species representation within existing protected areas. Existing protected areas in Spain and Portugal reasonably represented the plant and animal species we considered (73–98%). Nevertheless, species of some groups (amphibians, reptiles, birds, and gymnosperms) did not accumulate in protected areas at a rate higher than expected by chance ( p > 0.05). We determined that to conserve all vertebrate and plant species in the Iberian Peninsula, at least 36 additional areas are needed. Selection of additional areas for conservation would be facilitated if such areas coincided with sites of community importance (SCI) designated under the European Commission Habitats Directive. Additional areas required for full representation of the selected plant and animal species all coincide with SCI in Spain. Nevertheless, the degree of coincidence varies between 0.3% and 74.6%, and there is a possibility that important areas for conservation occur outside the SCI. Our results support the view that current SCI can be used for prioritization of areas for conservation, but a systematic reevaluation of conservation priorities in Spain and Portugal would be necessary to ensure that effective conservation of one of European's most important biodiversity regions is achieved. 相似文献
89.
张旋 《生态与农村环境学报》1996,(2)
雷公山自然保护区以秃杉等珍稀濒危物种和中亚热带山地森林生态系统为主要保护对象。10多年来,保护区在认真做好自然保护工作的同时,引导地方群众发展生产、脱贫致富,探索了许多适度开发当地资源的实用技术和有效的经济发展模式,促进了地方经济发展,改善了当地群众生活,增强了保护区经济活力。在分析保护区发展现状的基础上,针对目前存在问题,提出保护区今后发展的对策措施。 相似文献
90.
WEBGIS及其在环境管理上的应用 总被引:1,自引:0,他引:1
WebGIS是当前地理信息系统发展的一个重要方向,本文介绍了采用了Java技术和XML技术的新的WebGIS体系结构,并结合ArcIMS的定制开发,结合通化市污染物总量控制给出了吉林省环境保护行业的WebGIS应用系统开发实例. 相似文献