全文获取类型
收费全文 | 26654篇 |
免费 | 201篇 |
国内免费 | 139篇 |
专业分类
安全科学 | 461篇 |
废物处理 | 1423篇 |
环保管理 | 3470篇 |
综合类 | 4091篇 |
基础理论 | 7404篇 |
环境理论 | 10篇 |
污染及防治 | 5695篇 |
评价与监测 | 2019篇 |
社会与环境 | 2294篇 |
灾害及防治 | 127篇 |
出版年
2022年 | 128篇 |
2021年 | 137篇 |
2020年 | 114篇 |
2019年 | 140篇 |
2018年 | 1740篇 |
2017年 | 1672篇 |
2016年 | 1563篇 |
2015年 | 417篇 |
2014年 | 396篇 |
2013年 | 1357篇 |
2012年 | 963篇 |
2011年 | 2047篇 |
2010年 | 1312篇 |
2009年 | 1223篇 |
2008年 | 1622篇 |
2007年 | 2027篇 |
2006年 | 643篇 |
2005年 | 591篇 |
2004年 | 541篇 |
2003年 | 641篇 |
2002年 | 611篇 |
2001年 | 567篇 |
2000年 | 441篇 |
1999年 | 249篇 |
1998年 | 226篇 |
1997年 | 193篇 |
1996年 | 210篇 |
1995年 | 219篇 |
1994年 | 208篇 |
1993年 | 209篇 |
1992年 | 216篇 |
1991年 | 204篇 |
1990年 | 204篇 |
1989年 | 177篇 |
1988年 | 152篇 |
1987年 | 132篇 |
1986年 | 158篇 |
1985年 | 158篇 |
1984年 | 177篇 |
1983年 | 169篇 |
1982年 | 156篇 |
1981年 | 163篇 |
1980年 | 151篇 |
1979年 | 145篇 |
1978年 | 108篇 |
1977年 | 121篇 |
1974年 | 109篇 |
1973年 | 91篇 |
1972年 | 107篇 |
1971年 | 88篇 |
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
71.
72.
Ricardo Braun 《Environment, Development and Sustainability》2007,9(4):387-411
The implementation of sustainable development may seem a simple concept when written on paper. However to carry-out long term
actions put forward by the Agenda 21 (AG21) at the local level represents one of the main challenges as municipal governments
in general do not have the capacity to effectively implement the process.
Regional environmental assessment (REA) has shown to be effective in supporting decision-making not only to correct environmental
problems due to past unsustainable social-economic developments but also help local governments to implement sustainable actions.
However this requires long-term investments of AG21 plans and projects. The allocation of regular and consistent financial
resources is one of the main ingredients for the sustainable development process. But traditional plans and projects financed
by national and/or international funds may not be sustainable in the long-term because they become dependent on external funding.
Research demonstrate that innovative economic instruments such as ecotaxes represent a feasible alternative to sponsor local
sustainability because taxes are collected permanently by the government and could be invested in continuous actions. Ecotaxes
experiences have provided important reference to structure a municipal incentive model (MIM) to sponsor AG21’s environmental
plans and projects on a long-term (permanent) basis.
However sustainable development cannot be solely through economic investments. A comprehensive municipal environmental management
scheme (MEMS) has been established to support the incentive model. The scheme seeks not only to improve local institutional
framework but also incentive continuous participation of local stakeholders at all levels of society. Participatory events
and the provision of incentives (educational and financial) are key to motivate society to protect the environment and support
actively the sustainable development process as emphasised in the RIO-92 Conference. 相似文献
73.
Estimates of animal methane emissions 总被引:2,自引:0,他引:2
The enteric methane emissions into the atmospheric annually from domestic animals total about 77 Tg. Another 10 to 14 Tg are likely released from animal manure disposal systems. About 95% of global animal enteric methane is from ruminants, a consequence of their large populations, body size and appetites combined with the extensive degree of anaerobic microbial fermentation occurring in their gut. Accurate methane estimates are particularly sensitive to cattle and buffalo census numbers and estimated diet consumption. Since consumption is largely unknown and must be predicted, accuracy is limited often by the information required, i.e., distribution of animals by class, weight and productivity. Fraction of the diet lost as enteric methane mostly falls into the range of 5.5–6.5% of gross energy intake for the world's cattle, sheep and goats. Manure methane emissions are heavily influenced by fraction of disposal by anaerobic lagoon. Non-ruminants, i.e., swine, become major contributors to these emissions. 相似文献
74.
Community evacuation following a chlorine release, Mississippi 总被引:1,自引:0,他引:1
On 7th September 1986, four miles north of Collins, Mississippi, a train transporting chlorine derailed. Two cars ruptured and gas escaped. As a result, 100 families were evacuated. To study the evacuation process, we conducted person-to-person interviews with sixty-two families staying in the evacuation center. Only 52.5% of the families received their first directive to evacuate directly from police or other officials. Delays in evacuating tended to be shorter when people were warned by the police and were told the reason for evacuating. Lack of personal transportation and preexisting health problems resulted in delays in evacuation. Concerns about evacuation included fear of looting, lack of a place to go, lack of transportation, difficulty in moving with children and elderly persons, and the need to take care of pets. One third of the interviewees reported feeling panic. Community evacuation procedures would be improved if: (1) officials contact all households directly; (2) the warning message addresses people's concerns; and (3) transportation is provided. 相似文献
75.
76.
Indices of abundance and reproduction rate are considered in some groups of aquatic and terrestrial vertebrates from the zones of technogenic disasters. Upon a critical population decline caused by external destructive factors, such as emissions of acute ecotoxicants, the ecophysiological and behavioral compensatory mechanisms are activated, which provide for restoration of the total population size to the optimum within a short period of time. Environmental pollution with substances disturbing the reproductive function has the gravest consequences for animals. In this case, population size may remain fairly high, and, therefore, the effect of enhanced reproduction as a response to population decline does not take place, which eventually leads to a gradual but irreversible destruction of the population. Pathologies of reproduction should be used as a criterion for assessing the state of animals in the zones of technogenic disasters.Translated from Ekologiya, No. 1, 2005, pp. 32–38.Original Russian Text Copyright © 2005 by Shilova, Shatunovskii. 相似文献
77.
New data on the composition of surface assemblages of plant macroremains from soil and swamp samples have been obtained in the study of geomorphologically different localities in the middle reaches of the Nizhnyaya Tunguska River. The results of paleocarpological analysis of forest soil sections supported by relevant palynological and geochronological data are presented. Natural changes of the forest cover over the past 2400 years and quantitative characteristics of the paleoclimate during each stage are described.Translated from Ekologiya, No. 1, 2005, pp. 3–10.Original Russian Text Copyright © 2005 by Koshkarova, Koshkarov. 相似文献
78.
M. Marcelli M. Caburazzi A. Perilli V. Piermattei E. Fresi 《Chemistry and Ecology》2005,21(5):351-367
The towed undulating vehicle (TUV), named SARAGO, was used for two fine-scale surveys between the Italian and the Sardinian coasts during the Astraea 2 cruise (6-7 and 26-27 September 1995), studying the deep chlorophyll maximum distribution. SARAGO sections identify a sub-surface doming with higher chlorophyll a and primary production concentrations in the upwelling area of a cyclonic gyre region, detected by sea-surface temperature images. In the first section, the cyclone presents a double doming, in density and salinity, with shallower and concentrated patches of chlorophyll a for about 2 miles. Twenty days later, the second section shows that the gyre changes shape and extension, showing a single doming with higher primary production and chlorophyll a concentrations, distributed over a large area of about 40 nautical miles. SARAGO allows analysis of this high-variability phenomenon (cyclonic gyre) and allows concentrated patches (2 nm) to be identified, thus proving the importance of TUVs in the study of mesoscale processes. 相似文献
79.
Coping with riverbank erosion hazard and displacement in bangladesh: survival strategies and adjustments 总被引:2,自引:0,他引:2
As a deltaic plain, Bangladesh annually experiences riverbank erosion hazard due to sudden and rapid channel shifting, particularly in the major floodplain areas of the country. Consequently, valuable cultivable land is lost; also village settlements, markets and towns are destroyed, displacing tens of thousands of people. This paper examines the magnitude of river channel migration and encroachment on land, and the nature of human adjustment systems in the Brahmaputra–Jamuna floodplain, by investigating aspects of the social and cultural dynamics of resettlement of the displaced people. Some policy measures are recommended to improve the ability of the people in the floodplain to cope with these hazards. 相似文献
80.
This paper reviews six case studies examined as part of a project to review targetting methodologies employed by non-government organisations in Africa during the 1984-6 food crisis. Most agencies have not yet fully evaluated the role of data in informing policy decisions during their respective emergency programmes. The case studies presented reflect a wide variety of approaches to targetting emergency food aid that are based largely on the use of 'socio-economic' data. The recent emergency relief operations in Africa seem to indicate a change in relief agencies' approaches to the assessment and monitoring of needs of the affected populations. Earlier dependance on nutritional data has given way to an increasing reliance on the use of socio-economic indicators. There was a wide variation in the case studies of the type of indicators collected and utilised in needs assessment and monitoring. There were those who relied almost exclusively on nutritional data to target resources during the 1984-86 African crisis, and others whose experiences during that period lead them to attach more weight to socio-economic data. Other agencies appear to have recognised the problems of relying solely on nutritional data to target food aid during their 1984–86 emergency programmes, and thus more or less abandoned classical anthropometric surveys in their needs assessment and monitoring methodologies during this period. Thus nutritional data has a less significant role in the decision making process than previously had been the case. 相似文献