全文获取类型
收费全文 | 24598篇 |
免费 | 202篇 |
国内免费 | 133篇 |
专业分类
安全科学 | 530篇 |
废物处理 | 1227篇 |
环保管理 | 3565篇 |
综合类 | 4427篇 |
基础理论 | 6530篇 |
环境理论 | 9篇 |
污染及防治 | 5505篇 |
评价与监测 | 1716篇 |
社会与环境 | 1325篇 |
灾害及防治 | 99篇 |
出版年
2018年 | 1609篇 |
2017年 | 1513篇 |
2016年 | 1405篇 |
2015年 | 336篇 |
2014年 | 272篇 |
2013年 | 1171篇 |
2012年 | 844篇 |
2011年 | 1828篇 |
2010年 | 1076篇 |
2009年 | 1073篇 |
2008年 | 1372篇 |
2007年 | 1765篇 |
2006年 | 553篇 |
2005年 | 435篇 |
2004年 | 454篇 |
2003年 | 542篇 |
2002年 | 481篇 |
2001年 | 531篇 |
2000年 | 382篇 |
1999年 | 255篇 |
1998年 | 201篇 |
1997年 | 176篇 |
1996年 | 209篇 |
1995年 | 202篇 |
1994年 | 232篇 |
1993年 | 210篇 |
1992年 | 199篇 |
1991年 | 199篇 |
1990年 | 220篇 |
1989年 | 204篇 |
1988年 | 180篇 |
1987年 | 179篇 |
1986年 | 160篇 |
1985年 | 180篇 |
1984年 | 169篇 |
1983年 | 182篇 |
1982年 | 177篇 |
1981年 | 182篇 |
1980年 | 161篇 |
1979年 | 154篇 |
1978年 | 148篇 |
1977年 | 135篇 |
1976年 | 138篇 |
1975年 | 117篇 |
1974年 | 147篇 |
1973年 | 127篇 |
1972年 | 127篇 |
1971年 | 111篇 |
1970年 | 108篇 |
1967年 | 117篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Rita W. Driggers Helene Bernstein Michael Lantz Gail Stetten Cathleen S. Escallon Elizabeth Perlman Karin J. Blakemore 《黑龙江环境通报》2001,21(5):387-389
Non-mosaic trisomy 20 is rare in fetuses surviving beyond the first trimester. We report a case of a fetus with non-mosaic trisomy 20 in amniotic fluid cultures obtained during the prenatal evaluation of an unusual thoraco-abdominal mass which was found at autopsy to be pulmonary sequestration. Gross inspection and autopsy of the fetus revealed multiple anomalies. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
992.
消融的冰川:加拿大班夫国家公园亚高山带鲍湖中持久性有机氯的主要来源 总被引:2,自引:0,他引:2
Jules M. Blais David W. Schindler Derek C.G. Muir Martin Sharp David Donald Melissa Lafrenire Eric Braekevelt William M.J. Strachan 《Ambio-人类环境杂志》2001,30(7):410-415
有机氯杀虫剂和多氯联苯(PCB)是环境中普遍而稳固的化合物。现已查明,由于它们从温暖的地区逐渐蒸发出来,并在较冷的地区凝聚下来,因而它们富集在寒冷的环境中。在本研究中,我们的结果是,消融的冰川供给阿尔伯达亚高山带湖泊中的有机氯输入量为50%~97%,而提供的水量为73%。对氚的分析结果表明,在夏季的中、晚期,至少10%的冰川消融物是在1950~1970年期间沉积下来的,这期间它受到有机氯更多的污染。这一发现表明,气候变暖可能会使消融的冰川成为日益增多的淡水污染物来源。由于有机物贫乏的冰川粘土对多氯联苯这样的疏水化合物的吸附能力有限,因此冰川水流带来的有机氯大多呈溶解状态。 相似文献
993.
The British Columbia Ministry of Forests’ “Aboriginal Rights and Title — Consultation Guidelines”, prepared in response to a Supreme Court of Canada decision on aboriginal rights and title, presents an interesting example of how common law influences provincial environmental policy. The policy addresses the British Columbia government’s fiduciary duty to First Nations and requires staff to consult with aboriginals during operational forestry planning. Adequate understanding of the policy is essential for lawful forest management. The Consultation Guidelines have become a key environmental policy in British Columbia.This evaluation will increase understanding of the Consultation Guidelines and aboriginal title for forest practitioners and policy makers. Within the context of a Vancouver Island case study, the policy is analyzed in view of the following criteria: effectiveness, efficiency, equity, and effort. Even though the policy is over 2 years old and the government is actively managing forests in an area under negotiation for treaty, the policy has yet to be implemented. As a result, aboriginal concerns about the long-term environmental and economic sustainability of current forest practices go unheeded. This situation potentially jeopardizes the government’s ability to address its fiduciary responsibilities to aboriginals, as defined in case law and the Canadian Constitution. 相似文献
994.
This paper proposes an integrated ecological, economic and social model to assist sustainable rural development in villages in Bangladesh. In the model, renewable energy technologies (RETs) create income-generating activities for male landless and marginal farmers and for women from such households, while reducing environmental problems, like deforestation and indoor air pollution from cooking with poor-quality fuels. Because of the high capital costs of RETs, the model proposes an extension of the well-known micro-credit approach developed by such NGOs as the Grameen Bank and BRAC. With the assistance of an External Agency composed of NGO, business, government and university representatives, such groups of villagers would form Village Organizations, comprising cooperatives or other forms of business, borrow money from a bank or large NGO, and purchase a RET based on biogas, solar or wind, depending upon location. By selling energy to wealthier members of the village, the Village Organizations would repay their loans, thus gaining direct ownership and control over the technology and its applications. 相似文献
995.
IntroductionChengdu KunmingRailwayLineislocatedonthemountainregionofsouthwesternChina .Therearealotofdebrisflowgulliesspreadingbesidethisrailwayline .Onsummer,thedebrisflowoftenburstsandthreatensthesafetyoftherailwaytransportation.In 1981,alarge scaledebris… 相似文献
996.
997.
W. Nentwig 《Die Naturwissenschaften》1999,86(9):411-421
Ecology is defined as the set of complex interactions between the biotic and abiotic environments. Human ecology concerns
principally the population ecology "only" of Homo sapiens, but it also includes all aspects of global ecology because humans are the most important species. Human demography is characterized
by a recent decline in mortality and fertility rates. These demographic transitions have largely been completed in industrialized
countries, but not in the 140 developing countries. Approximately 100 countries are following the same demographic pattern
as industrialized countries, however with a time delay of several generations. China has effectively reduced its population
increase by means that would be unacceptable in Western democracies. Some 44 developing countries still show increasing population
growth and no detectable demographic transition in birth rate. Thus one part of the world shows limited (and, in the long
run, shrinking) population growth, and another continues with a strong increase. All populations are limited in their development
by their sustainability by their environment, for example, food and energy resources, and the extent of pollution which the
use of these resources produces. It is argued that in the case of human population the limits of sustainability have already
been reached with the 6 billion humans alive today, since at least 20% of these suffer from hunger, natural resources are
overexploited, and biodiversity is threatened. In the coming 200 years it is more likely that the total population will substantially
oscillate rather than approach the predicted 12 billion. The most important goal of human ecology should therefore be to slow
population growth as far as possible. 相似文献
998.
Although international negotiation on the mitigation of climate change is a process of determining burden-sharing rules between countries, there has been no clear agreement on equity principles for burden sharing. During the negotiating process up to the Kyoto Protocol, various proposals were made on such burden-sharing rules, but an agreement on emission targets for Annex I countries was achieved without explicitly agree-ing to any rules. In the next phase of the negotiation, debates on emission targets are likely to shift from those between developed countries to those between all parties to the convention. In such a phase, debates on burden-sharing rules will be revisited. The purpose of this paper is: (1) to determine implicitly a formula for the rule for burden sharing between Annex I countries that was considered to be underlying the emission targets of the Kyoto Protocol, and (2) to examine plausible emission targets and timing of commitments for non-Annex I countries in the future by using the result of the analysis on the Kyoto Protocol. A multi-regression method is used for this purpose. It was concluded that the burden sharing between Annex I countries in the Kyoto Protocol can mostly be explained by three variables: the increase in the rate of CO2 emission during the years 1990 to 2010, the increase in the rate of afforestation between 1990 and 1995, and the GDP per capita at the time of negotiation. The timing of future commitments of developing countries and the levels of targets differ widely, depending on which index or formula is agreed as “equitable”. Some of the developing countries would have to start limiting their emissions within several years if GDP per capita or CO2 per capita were chosen as the burden-sharing indicator. Developing countries would not have to make commitments until the mid-late 21st century if population growth rate were chosen. If the inferred formula of the Kyoto Protocol were applied to developing countries, they would have had to start mild limitation from 1990. 相似文献
999.
1000.