全文获取类型
收费全文 | 3790篇 |
免费 | 337篇 |
国内免费 | 36篇 |
专业分类
安全科学 | 581篇 |
废物处理 | 31篇 |
环保管理 | 1478篇 |
综合类 | 942篇 |
基础理论 | 541篇 |
环境理论 | 7篇 |
污染及防治 | 85篇 |
评价与监测 | 94篇 |
社会与环境 | 210篇 |
灾害及防治 | 194篇 |
出版年
2024年 | 59篇 |
2023年 | 95篇 |
2022年 | 100篇 |
2021年 | 107篇 |
2020年 | 109篇 |
2019年 | 154篇 |
2018年 | 130篇 |
2017年 | 171篇 |
2016年 | 153篇 |
2015年 | 150篇 |
2014年 | 137篇 |
2013年 | 189篇 |
2012年 | 229篇 |
2011年 | 218篇 |
2010年 | 150篇 |
2009年 | 170篇 |
2008年 | 142篇 |
2007年 | 179篇 |
2006年 | 169篇 |
2005年 | 121篇 |
2004年 | 107篇 |
2003年 | 101篇 |
2002年 | 90篇 |
2001年 | 81篇 |
2000年 | 78篇 |
1999年 | 90篇 |
1998年 | 53篇 |
1997年 | 49篇 |
1996年 | 60篇 |
1995年 | 56篇 |
1994年 | 42篇 |
1993年 | 29篇 |
1992年 | 41篇 |
1991年 | 20篇 |
1990年 | 13篇 |
1989年 | 15篇 |
1988年 | 16篇 |
1987年 | 22篇 |
1986年 | 22篇 |
1985年 | 25篇 |
1984年 | 24篇 |
1983年 | 14篇 |
1980年 | 17篇 |
1979年 | 18篇 |
1978年 | 23篇 |
1977年 | 16篇 |
1975年 | 12篇 |
1973年 | 17篇 |
1972年 | 16篇 |
1971年 | 18篇 |
排序方式: 共有4163条查询结果,搜索用时 15 毫秒
91.
Don A. Driscoll Georgia E. Garrard Alexander M. Kusmanoff Stephen Dovers Martine Maron Noel Preece Robert L. Pressey Euan G. Ritchie 《Conservation Letters》2021,14(1):e12757
Suppressing expert knowledge can hide environmentally damaging practices and policies from public scrutiny. We surveyed ecologists and conservation scientists from universities, government, and industry across Australia to understand the prevalence and consequences of suppressing science communication. Government (34%) and industry (30%) respondents reported higher rates of undue interference by employers than did university respondents (5%). Internal communications (29%) and media (28%) were curtailed most, followed by journal articles (11%), and presentations (12%). When university and industry researchers avoided public commentary, this was mainly for fear of media misrepresentation, while government employees were most often constrained by senior management and workplace policy. One third of respondents reported personal suffering related to suppression, including job losses and deteriorating mental health. Substantial reforms are needed, including to codes of practice, and governance of environmental assessments and research, so that scientific advice can be reported openly, in a timely manner and free from interference. 相似文献
92.
Dickella Gamaralalage Jagath Premakumara Aloysius Mariae L. Canete Masaya Nagaishi Tonni Agustiono Kurniawan 《Waste management (New York, N.Y.)》2014,34(6):971-979
Municipal Solid Waste Management (MSWM) is considered to be one of the most serious environmental issues in the Philippines. The annual waste generation was estimated at 10.6 million tonnes in 2012 and this is expected to double in 2025. The Republic Act (RA) No. 9003, widely known as the Ecological Solid Waste Management Act of 2000, provides the required policy framework, institutional mechanisms and mandate to the Local Government Units (LGUs) to achieve 25% waste reduction target through establishing an integrated solid waste management plan based on the 3Rs (reduce, reuse and recycling). Although the initial impact of the LGUs is still very limited in implementing the national mandate, this article highlights the successful experiences of Cebu, the second largest city in the Philippines, in reducing its MSW generation by more than 30% in the past three years. This study also explores the implementation process, innovative actions taken by the Cebu City Government in implementing the national mandate at local level and identifies the factors that influence the policy implementation. The findings suggest that the impacts of the national mandate can be achieved if the LGUs have the high degree of political commitment, planning and development of effective local strategies in a collaborative manner to meet with local conditions, partnership building with other stakeholders, capacity development, adequate financing and incentives, and in the close monitoring and evaluation of performance. 相似文献
93.
模糊支持向量机(FSVM)综合了模糊理论和支持向量机(SVM)的学习理论,不仅继承了SVM在小样本情况下所具有的较强识别能力的特点,并且比SVM拥有更好的学习能力。在FSVM算法中,每个样本被赋予一个隶属度值,使得构造目标函数时不同的样本有不同的贡献,达到最大限度的消除噪声或者孤立点的效果。运用了灰色关联分析(GRA)对煤与瓦斯突出指标进行提取,引入了一个合适的模糊隶属度函数,并在此基础上提出了基于FSVM的煤与瓦斯突出预测的模型,通过实际数据的验证和其他预测方法的对比,证明了FSVM模型能够满足煤与瓦斯突出预测的要求。最后,将FSVM和传统SVM对同一组数据进行训练,证明了FSVM相比较传统SVM拥有更高的精确度。 相似文献
94.
George Mulamoottil Robert Farvolden 《Journal of the American Water Resources Association》1975,11(3):599-604
ABSTRACT: By field investigations and planning, it is profitable to rehabilitate gravel pits as recreational lakes in urban areas. Some of the important aspects to be considered are topography, soil, surface water and groundwater. A case study is presented and some general guidelines in the rehabilitation process are given. This kind of a use for derelict land is important at the present time as there is a growing demand for recreational lakes in urban areas. 相似文献
95.
Robin Hickman Patricia Austin David Banister 《Journal of Environmental Policy & Planning》2014,16(3):419-435
AbstractA number of cities around the world are associated with very high levels of private motor car usage, and Auckland provides an example of one of these ‘hyperautomobile’ cities. There are many problems with this system of transportation and dependence on the private car, including environmental, social and city design dimensions. Though there is a clear aspiration to move towards reduced levels of car usage in the city's transport and spatial planning strategies, there are major difficulties in implementation terms. We develop and consider future scenarios to 2041 to reduce these levels of motorization, and subsequent transport CO2 emissions, with a much greater use of public transport, walking and cycling, urban planning, and low emission vehicles. The current implementability of such a ‘sustainable mobility’ future is however questioned in the current political and social context, and critically debated in terms of the available governance mechanisms and the limited attempts to shape the behaviour of the public. We conclude by calling for a reconsideration of the policy measures being considered, including the range and levels of application and investment; with a much wider framing of the transport planning remit, and carried out within a much stronger participatory framework for decision-making. 相似文献
96.
Forest growth models are useful tools for investigating the long-term impacts of logging. In this paper, the results of the rain forest growth model FORMIND were assessed by a multicriteria decision analysis. The main processes covered by FORMIND include tree growth, mortality, regeneration and competition. Tree growth is calculated based on a carbon balance approach. Trees compete for light and space; dying large trees fall down and create gaps in the forest. Sixty-four different logging scenarios for an initially undisturbed forest stand at Deramakot (Malaysia) were simulated. The scenarios differ regarding the logging cycle, logging method, cutting limit and logging intensity. We characterise the impacts with four criteria describing the yield, canopy opening and changes in species composition. Multicriteria decision analysis was used for the first time to evaluate the scenarios and identify the efficient ones. Our results plainly show that reduced-impact logging scenarios are more 'efficient' than the others, since in these scenarios forest damage is minimised without significantly reducing yield. Nevertheless, there is a trade-off between yield and achieving a desired ecological state of logged forest; the ecological state of the logged forests can only be improved by reducing yields and enlarging the logging cycles. Our study also demonstrates that high cutting limits or low logging intensities cannot compensate for the high level of damage caused by conventional logging techniques. 相似文献
97.
D. S. Gunby 《Journal of Environmental Planning and Management》1987,30(1):6-12
This paper analyses the currents which gave rise to the 1947 Town & Country Planning Act. It describes the main statutory events in the first half of the 20th century and considers the progress made in implementing the legislation. It is argued that, while the 1947 Act was a major advance on what went before, it is not a significant departure. 相似文献
98.
Chien-Hsiung Chen Wen-Chih Chang Wen-Te Chang 《Journal of environmental psychology》2009,29(2):220-226
This study investigated user wayfinding navigational performance in terms of two navigational support designs (guide sign and you-are-here map, i.e., YAH), wayfinding strategies (egocentric/route and allocentric/survey), task difficulty (terrestrial/2D or weightless/3D), and gender differences. Eighty participants (40 males and 40 females) were recruited for the wayfinding experiment. The experimental results and statistical analysis indicated that, in the weightless VR scene, navigation time for the terrestrial/2D task type was significantly shorter than for the weightless/3D task type. The guide sign support was significantly more effective than YAH map support. Moreover, the interactions between support style and gender difference indicated that males exhibit better wayfinding performance than females, but that appropriate support can improve navigational performance and eliminate gender differences. In addition, the Way-Finding Strategy Scale result showed that the females were more likely to adopt the egocentric strategy while males were more likely to adopt the allocentric strategy, and that their scores were negatively correlated with navigational performance. Our results can be used to evaluate the interface designs of navigational support systems taking into consideration gender differences with respect to 3D VR games, including VR diving or flying navigational systems. 相似文献
99.
Linden F Vincent 《Natural resources forum》2003,27(2):108-116
Situations of water scarcity challenge sustainability and threaten small users' access to water. In response to this problem, there has been a search for a method of hydrological analysis that can better represent the needs of small water users. While this search is rooted in the debate favouring a more participatory and inclusive allocation of the resource, it also requires a new focus on smallholder hydrology that can confront the gaps and biases found in current hydrological practices in many countries. This article looks at past hydrological practices and also at results of recent studies, highlighting the perspective of smallholder irrigators in surface water planning in Zimbabwe, and groundwater planning in India. These case studies show that wider social forces, not always best science, drive hydrological practices. However, new frameworks focusing on the water user can emerge for more equitable and sustainable water management. 相似文献
100.
A study of a watershed planning process in the Cache River Watershed in southern Illinois revealed that class divisions, based
on property ownership, underlay key conflicts over land use and decision-making relevant to resource use. A class analysis
of the region indicates that the planning process served to endorse and solidify the locally-dominant theory that landownership
confers the right to govern. This obscured the class differences between large full-time farmers and small-holders whose livelihood
depends on non-farm labor. These two groups generally opposed one another regarding wetland drainage. Their common identity
as “property owner” consolidated the power wielded locally by large farmers. It also provided an instrument – the planning
document – for state and federal government agencies to enhance their power and to bring resources to the region. The planning
process simultaneously ameliorated conflicts between government agencies and the large farmers, while enhancing the agencies’
capacity to reclaim wetlands. In this contradictory manner, the plan promoted the environmental aims of many small-holders,
and simultaneously disempowered them as actors in the region’s political economy.
An erratum to this article is available at . 相似文献