全文获取类型
收费全文 | 7770篇 |
免费 | 519篇 |
国内免费 | 1088篇 |
专业分类
安全科学 | 535篇 |
废物处理 | 84篇 |
环保管理 | 2088篇 |
综合类 | 3705篇 |
基础理论 | 766篇 |
污染及防治 | 409篇 |
评价与监测 | 1278篇 |
社会与环境 | 388篇 |
灾害及防治 | 124篇 |
出版年
2024年 | 42篇 |
2023年 | 128篇 |
2022年 | 172篇 |
2021年 | 209篇 |
2020年 | 227篇 |
2019年 | 174篇 |
2018年 | 163篇 |
2017年 | 254篇 |
2016年 | 313篇 |
2015年 | 303篇 |
2014年 | 372篇 |
2013年 | 496篇 |
2012年 | 488篇 |
2011年 | 562篇 |
2010年 | 395篇 |
2009年 | 401篇 |
2008年 | 338篇 |
2007年 | 517篇 |
2006年 | 486篇 |
2005年 | 369篇 |
2004年 | 336篇 |
2003年 | 326篇 |
2002年 | 306篇 |
2001年 | 240篇 |
2000年 | 232篇 |
1999年 | 185篇 |
1998年 | 149篇 |
1997年 | 145篇 |
1996年 | 142篇 |
1995年 | 106篇 |
1994年 | 97篇 |
1993年 | 74篇 |
1992年 | 61篇 |
1991年 | 62篇 |
1990年 | 32篇 |
1989年 | 34篇 |
1988年 | 40篇 |
1987年 | 32篇 |
1986年 | 25篇 |
1985年 | 27篇 |
1984年 | 34篇 |
1983年 | 29篇 |
1982年 | 34篇 |
1981年 | 29篇 |
1980年 | 32篇 |
1979年 | 30篇 |
1978年 | 23篇 |
1975年 | 15篇 |
1973年 | 20篇 |
1972年 | 15篇 |
排序方式: 共有9377条查询结果,搜索用时 515 毫秒
991.
The aim of this study is to analyze the environmental agenda in Sweden during the last two decades. A content analysis was made of all articles in a Swedish journal,Miljö-Aktuellt. Further, to elucidate the evolutionary process of problem formulation and reformulation, two cases were investigated, dealing with the impact of plant nutrients and mercury on surface water quality. The transport of heavy metals is an essential component of the ecological process and problem of acidification, and similarly, plant nutrients are part of the concept of eutrophication. Two concepts, the research cycle and the policy cycle, are tentatively applied to the conceptualizations of acidification and eutrophication. Additional data for the latter part of the study is supplied from parliamentary motions during 1973–1989. The substance/media focus of the 1970s was connected to a point-source abatement strategy, which mainly aimed at removing negative effects at a local level. The development of a national preventive strategy is traced in problem formulations related to “processes” going on in the technosphere: wastes, noise, energy production, traffic, and toxic substances. This period lasted from the mid-1970s to the mid-1980s, and the need for improved resource management as a means to control environmental problems has been a generally accepted idea. However, this does not mean that measures actually taken are sufficient in a material balance perspective. Further, in the 1980s there was a strong emphasis upon processes in the ecosphere. This focus also implies source-related policies. To a certain extent, the remedies are within the scope of national capabilities, but the international dimension is becoming increasingly important. Scientific proofs of resource and environment degradation are essential to induce political action and to stimulate international cooperation. From this study, however, it is not possible to assess the existence of any particular policy-triggering information. 相似文献
992.
黄伟雄 《中国人口.资源与环境》2002,(5)
本文从资源、环境和人地关系的角度探讨我国的可持续发展问题 ,分析了影响我国可持续发展因素 ,指出中华民族的人口素质是我国可持续发展的关键 ,阐明科教兴国是我国可持续发展的必由之路 相似文献
993.
Marek Makowski Lszl Somlydy David Watkins 《Journal of the American Water Resources Association》1996,32(5):937-951
ABSTRACT: This paper presents the implementation of one element of a decision support system (DSS) for regional water quality management, applied to the Nitra River Basin in Slovakia. A model-based, aspiration-led methodology for multicriteria decision support has been used for the study. Several reusable, modular software tools have been developed and implemented: a problem-specific generator to produce the core part of the mathematical programming model, tools for the generation and interactive modification of multicriteria problems, and a solver for the resulting mixed-integer optimization problem. Provided in the paper are the following: a complete formulation of the mathematical model (including the imbedded water quality model), a summary of the aspiration-reservation-led multiple criteria optimization approach applied to decision support, and an overview of results that illustrate the applied approach and provide some interesting insights to the case study. 相似文献
994.
Acute toxicity and presumable harmless concentration of two commercial insecticides, Furadan 3G and Malataf 50E were reported for tubificid worms, Tubifex tubifex and Limnodrilus hoffmeisteri. L. hoffmeisteri were found more susceptible to both the insecticides; the Furadan was found to be more toxic than Malataf to tubificid worms. Analysis of variants showed a significant difference between safe concentrations of the same insecticide to different species. 相似文献
995.
Franziska?Pfister Peter?BacciniEmail author 《Environment, Development and Sustainability》2005,7(3):337-361
Food production has to be increased in a sustainable way to meet the future global demand. A key position is attributed to
developing countries. A deepened understanding of their agricultural regions with specific resource endowments and constraints
is therefore crucial. In this study we propose a methodology based on material flux analysis (MFA) to assess the resource
potentials and limitations of a Nicaraguan agricultural region. We focus on current regional and farm resource management
and explore them under two scenarios. Indicators are nitrogen and the degrees of self-sufficiency (DSS) for energy, and the
staples maize and beans. As data is scarce, most information is based on interviews with farmers of four categories and key
persons, and on literature.
The results show that nitrogen management does not differ considerably among categories. Nitrogen is mined mostly from staple
plots. Self-sufficiency for beans is given in an average year. Yet, landless and small farmers neither produce enough maize
for autoconsumption, nor are they self-sufficient for firewood. Energy supply is also the core problem of the region, since
the DSS is 70%. Soil nitrogen
stocks last at most for three more generations. Analyses with the scenario technique show that: (a) Unlimited population growth
has serious consequences in the near future e.g. severe shortage of energy and food. (b) Alternative farming systems are possible,
but they require reducing the population by a factor 2, and thus the creation of jobs in a Hinterland.
Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
996.
Marco Keiner 《Environment, Development and Sustainability》2005,6(4):379-392
The principle of sustainable development is now 15-year-old. There are a lot of definitions and models for its explanation — ranging from triangles and prisms to eggs — but still its sense is diffuse. Moreover, important aspects like equity are not sufficiently taken into account.The following article takes a critical look on sustainable development. It shows logical, systemic, philosophic and ethic reasons for the re-development of substantial parts of the principle of sustainability. Based on the proposed Principle of Good Heritage it provides a rough outline of a future Concept of Evolutionability, comprising a first tentative for a definition of evolutionable development, aiming at achieving a more appropriate and more workable mainstream view of sustainability.Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
997.
试论改善发展的质量 总被引:2,自引:0,他引:2
毛文永 《中国人口.资源与环境》1995,5(2):23-26
本文结合中国国情,从经济发展的目标、边界、途径等方面论述了改善发展质量的基本内涵,提出经济发展应以满足社会基本需要为目标,经济发展必须与环境和资源的承载力相适应,依靠科技进步是提高发展质量的根本途径,同时须不断改善经济的内部结构,走资源节。 相似文献
998.
区域生态环境评价的灰色关联投影模型 总被引:11,自引:0,他引:11
区域生态环境评价是实现全面环境管理,协调区域经济发展与生态环境保护.实现区域可持续发展的重要手段。由于评价所涉及的地域复杂性和因素多样性,许多评价方法和体系都处于不断探索和发展之中。区域生态环境系统是一个灰色系统,包括了自然、经济和社会等方面具有信息不确知性和不完全性的因素。基于灰色系统理论和矢量投影原理,建立了区域生态环境评价的灰色关联投影模型。该模型将评价样本及各级质量标准视为矢量.分别向同一矢量(理想样本)进行投影。根据投影值的大小,确定样本所属的生态环境质量级别及样本间的优劣排序。以巢湖流域为个案,在建立生态环境评价指标体系和标准的基础上,运用所建模型对其生态环境质量现状进行了评价,结果与实际情况相吻合。即巢湖流域总体以及分区合肥市、六安市的生态环境质量为4级,分区巢湖市为5级。研究表明,灰色关联投影模型对于多指标的区域生态环境质量评价是科学的、有效的,具有一定的推广和实用价值。 相似文献
999.
1000.
分析了润滑油基础油在储运过程中,油品质量可能产生的不良变化和对周围环境造成的危害.针对这些危害提出了解决的对策. 相似文献