全文获取类型
收费全文 | 18473篇 |
免费 | 1032篇 |
国内免费 | 3051篇 |
专业分类
安全科学 | 1052篇 |
废物处理 | 1091篇 |
环保管理 | 1981篇 |
综合类 | 7116篇 |
基础理论 | 4571篇 |
污染及防治 | 3305篇 |
评价与监测 | 1597篇 |
社会与环境 | 1454篇 |
灾害及防治 | 389篇 |
出版年
2024年 | 52篇 |
2023年 | 175篇 |
2022年 | 538篇 |
2021年 | 567篇 |
2020年 | 565篇 |
2019年 | 393篇 |
2018年 | 1851篇 |
2017年 | 1815篇 |
2016年 | 1614篇 |
2015年 | 697篇 |
2014年 | 699篇 |
2013年 | 869篇 |
2012年 | 1249篇 |
2011年 | 2156篇 |
2010年 | 1414篇 |
2009年 | 1335篇 |
2008年 | 1571篇 |
2007年 | 1856篇 |
2006年 | 595篇 |
2005年 | 409篇 |
2004年 | 327篇 |
2003年 | 297篇 |
2002年 | 355篇 |
2001年 | 257篇 |
2000年 | 208篇 |
1999年 | 135篇 |
1998年 | 154篇 |
1997年 | 81篇 |
1996年 | 77篇 |
1995年 | 52篇 |
1994年 | 44篇 |
1993年 | 31篇 |
1992年 | 23篇 |
1991年 | 22篇 |
1990年 | 18篇 |
1989年 | 9篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 13篇 |
1983年 | 12篇 |
1982年 | 2篇 |
1975年 | 1篇 |
1935年 | 2篇 |
1923年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 562 毫秒
501.
Integrated strategies to reduce vulnerability and advance adaptation,mitigation, and sustainable development 总被引:4,自引:1,他引:3
Indur M. Goklany 《Mitigation and Adaptation Strategies for Global Change》2007,12(5):755-786
Determinants of adaptive and mitigative capacities (e.g., availability of technological options, and access to economic resources,
social capital and human capital) largely overlap. Several factors underlying or related to these determinants are themselves
indicators of sustainable development (e.g., per capita income; and various public health, education and research indices).
Moreover, climate change could exacerbate existing climate-sensitive hurdles to sustainable development (e.g., hunger, malaria,
water shortage, coastal flooding and threats to biodiversity) faced specifically by many developing countries. Based on these
commonalities, the paper identifies integrated approaches to formulating strategies and measures to concurrently advance adaptation,
mitigation and sustainable development. These approaches range from broadly moving sustainable development forward (by developing
and/or nurturing institutions, policies and infrastructure to stimulate economic development, technological change, human
and social capital, and reducing specific barriers to sustainable development) to reducing vulnerabilities to urgent climate-sensitive
risks that hinder sustainable development and would worsen with climate change. The resulting sustainable economic development
would also help reduce birth rates, which could mitigate climate change and reduce the population exposed to climate change
and climate-sensitive risks, thereby reducing impacts, and the demand for adaptation. The paper also offers a portfolio of
pro-active strategies and measures consistent with the above approaches, including example measures that would simultaneously
reduce pressures on biodiversity, hunger, and carbon sinks. Finally it addresses some common misconceptions that could hamper
fuller integration of adaptation and mitigation, including the notions that adaptation may be unsuitable for natural systems,
and mitigation should necessarily have primacy over adaptation.
相似文献
Indur M. GoklanyEmail: |
502.
The double trade-off between adaptation and mitigation for sea level rise: an application of FUND 总被引:6,自引:2,他引:4
Richard S. J. Tol 《Mitigation and Adaptation Strategies for Global Change》2007,12(5):741-753
This paper studies the effects of adaptation and mitigation on the impacts of sea level rise. Without adaptation, the impact
of sea level rise would be substantial, almost wiping out entire countries by 2100, although the globally aggregate effect
is much smaller. Adaptation would reduce potential impacts by a factor 10–100. Adaptation would come at a minor cost compared
to the damage avoided. As adaptation depends on socio-economic status, the rank order of most vulnerable countries is different
than the rank order of most exposed countries. Because the momentum of sea level rise is so large, mitigation can reduce impacts
only to a limited extent. Stabilising carbon dioxide concentrations at 550 ppm would cut impacts in 2100 by about 10%. However,
the costs of emission reduction lower the avoided impacts by up to 25% (average 10%). This is partly due to the reduced availability
of resources for adaptation, and partly due to the increased sensitivity to wetland loss by adaptation.
相似文献
Richard S. J. TolEmail: |
503.
Preety M. Bhandari Suruchi Bhadwal Ulka Kelkar 《Mitigation and Adaptation Strategies for Global Change》2007,12(5):919-933
India occupies 2.4% of the world’s geographical area with a large percentage of its land under agriculture. About 228 Million
hectares (Mha) of its geographical area (nearly 69%) fall within the dryland (arid, semi-arid and dry sub-humid) region. Of
the total cultivated area of 142 Mha, major part of agriculture in the country is rainfed, extending to over 97 Mha and constituting
nearly 68% of the net cultivated area, therefore making the agricultural sector vulnerable and exposed to the vagaries of
weather conditions. Climate change adds to this dimension of stress. A strong need is felt for targeting programmes in these
areas that address issues related to employing suitable soil and water conservation measures. In this context this paper seeks
to examine the case for watershed development as an adaptive strategy. An examination of the possibility of fortifying the
existing programme with a view to adapting to expected changes in climate in future is undertaken. Also, the possibility of
watershed development integrating into a suitable mitigation strategy for the country is assessed.
相似文献
Preety M. BhandariEmail: |
504.
U. Martin Persson Christian Azar 《Mitigation and Adaptation Strategies for Global Change》2007,12(7):1277-1304
The possibility of adopting national targets for carbon dioxide (CO2) emissions from tropical deforestation in a future international climate treaty has received increasing attention recently.
This attention has been prompted by proposals to this end and more intensified talks on possible commitments for developing
countries beyond the United Nations Framework Convention on Climate Change Kyoto Protocol. We analyze four main scientific
and political challenges associated with national targets for emissions from tropical deforestation: (1) reducing the uncertainties
in emission inventories, (2) preserving the environmental integrity of the treaty, (3) promoting political acceptance and
participation in the regime, and (4) providing economic incentives for reduced deforestation. We draw the following conclusions.
(1) Although there are large uncertainties in carbon flux from deforestation, these are in the same range as for other emissions
included in the current Kyoto protocol (i.e., non-CO2 GHGs), and they can be reduced. However, for forest degradation processes the uncertainties are larger. A large challenge
lies in building competence and institutions for monitoring the full spectrum of land use changes in developing countries.
(2 and 3) Setting targets for deforestation is difficult, and uncertainties in future emissions imply a risk of creating ‘tropical
hot air’. However, there are proposals that may sufficiently deal with this, and these proposals may also have the advantage
of making the targets more attractive, politically speaking. Moreover, we conclude that while a full carbon accounting system
will likely be politically unacceptable for tropical countries, the current carbon accounting system should be broadened to
include forest degradation in order to safeguard environmental integrity. (4) Doubts can be cast over the possible effect
a climate regime alone will have on deforestation rates, though little thorough analysis of this issue has been made.
相似文献
U. Martin PerssonEmail: |
505.
从一起爆炸事故的原因--没有办理设备检修许可证,分析了使用作业安全票证(单)存在的问题,提出了加强作业安全票证(单)管理措施. 相似文献
506.
1杭州湾海底输油管道及其海域基本情况杭州湾位于浙江省北部、上海市南部,东有舟山群岛,西有钱塘江注入,海底敷设有3条平行且相距50m的φ711mm、φ762mm、φ273mm管道,输送进口原油和石脑油。海底管道由慈溪新浦镇半掘浦下海,至平湖全塘镇白沙湾上岸,每条长55.6km。北岸(白沙湾)5km地形起伏较大,中段45km地势平坦,最高点在南岸海塘前沿, 相似文献
507.
红枫湖钻孔沉积物中滴滴涕的沉积记录 总被引:1,自引:0,他引:1
采用GC/MS方法分析了红枫湖钻孔沉积物中滴滴涕的垂直分布状况,并对其来源和生态风险进行了分析和评估.红枫湖钻孔沉积物中滴滴涕的含量介于7.6~23.7ng/g之间,且从底层至表层基本上呈下降的趋势.其中,1981~1983年间有一个急剧下降的过程,随后基本上呈缓慢下降的趋势.沉积物中滴滴涕的组成以p,p′-DDTs(p,p′-DDT、p,p′-DDE和p,p′-DDD的总和)为主,p,p′-DDTs与o,p′-DDTs(o,p′-DDT、o,p′-DDE和o,p′-DDD总和)的比值在5.1~8.4之间,说明沉积物中的滴滴涕主要来源于农药滴滴涕的残留.又因为沉积物中残留的滴滴涕是以它的代谢产物为主,DDT/(DDD+DDE)的比值为0.31~0.84,所以沉积物中的滴滴涕主要源于历史的残留.此外,DDT/(DDD+DDE)和DDE/DDD比值的垂直变化特征显示,尽管我国1983年就禁止了滴滴涕在农业上的使用,但直至1990年前后,红枫湖流域内仍存在滴滴涕使用的可能.风险评价的结果显示,红枫湖表层沉积物中DDE、DDD、DDT和DDTs的含量均介于ERL和ERM值之间,可能造成潜在的生态风险,因此红枫湖沉积物中滴滴涕的污染仍值得密切关注. 相似文献
508.
When encountering an already parasitized host, a parasitoid’s optimal choices (superparasitism, host rejection, host feeding
or infanticide) seem to depend on the individual species’ life history, because the same choice may have different fitness
consequences. We demonstrate infanticide under laboratory conditions by a polysphinctine, Zatypota albicoxa, which is a solitary koinobiont ectoparasitoid of spiders. The female always removed any previously attached egg or larva
from the body of the host spider, Parasteatoda tepidariorum, with a rubbing behaviour. She rubbed her ovipositor back and forth toward the undersurface of the attached egg or of the
saddle under the attached larva to pry it off and laid an egg after removal. When removing a larva, the infanticidal female
engaged exclusively in unfastening the ‘saddle’ which fastens the larva to the body of the spider. All larvae were removed
with the ‘saddle’ attached to the ventral surface of the body. The female invested more time to remove the medium second and
the large penultimate instar larvae than to remove eggs and first instar larvae because of the labour involved in unfastening
the saddle. Oviposition with infanticide of the medium second and the penultimate instar larvae imposed more time upon the
female than that on an unparasitized host. Removal of any previous occupant in spite of the associated labour costs suggests
that infanticide will always be adaptive, no matter the time costs to Z. albicoxa, because so much is invested in attacking the host and because the parasitoid cannot detect whether the spider is already
parasitized until she achieves subjugation. 相似文献
509.
Communication is shaped and constrained by the signaling environment. In aquatic habitats, turbidity can reduce both the quantity
and quality of ambient light and has been implicated in the breakdown of visual signaling. Here, we examined the relationship
between turbidity (quantified with long-term data) and the expression of carotenoid-based nuptial coloration in the red shiner
(Cyprinella lutrensis), a small-bodied cyprinid. Males in more turbid habitats displayed redder fins, and an experimental manipulation of adult
diet suggested that carotenoid intake alone did not explain among-population color differences. These results run counter
to similar studies where signal expression decreased in turbid conditions, and may be explained by the non-territorial red
shiner mating system, interactions between the mechanism of coloration and the signaling environment, or reduced cost of color
expression in turbid habitats (e.g., reduced predation risk). Our results highlight how the behavioral and ecological contexts
in which signals function can shape evolutionary responses to the environment. 相似文献
510.
A new mass estimate for the dodo (Raphus cucullatus), based on the lengths of the femur, tibiotarsus and tarsometatarsus, is attempted. The obtained mean mass is 10.2 kg, which
is less than previous estimates based on other methods, which ranged from 10.6 to 21.1 kg, and much lower than the 50 lbs
reported by a seventeenth-century eyewitness. The new estimated mass, which is similar to that of a large wild turkey, seems
more realistic than previous ones and supports the hypothesis that contemporary illustrations of extremely fat dodos were
either exaggerations, or based on overfed specimens. Pictures of “fat” dodos may also have been based on individuals exhibiting
a display behaviour with puffed out feathers. 相似文献