全文获取类型
收费全文 | 7527篇 |
免费 | 156篇 |
国内免费 | 93篇 |
专业分类
安全科学 | 344篇 |
废物处理 | 309篇 |
环保管理 | 1502篇 |
综合类 | 1001篇 |
基础理论 | 1881篇 |
环境理论 | 10篇 |
污染及防治 | 1755篇 |
评价与监测 | 553篇 |
社会与环境 | 346篇 |
灾害及防治 | 75篇 |
出版年
2023年 | 81篇 |
2022年 | 129篇 |
2021年 | 155篇 |
2020年 | 111篇 |
2019年 | 110篇 |
2018年 | 217篇 |
2017年 | 233篇 |
2016年 | 300篇 |
2015年 | 187篇 |
2014年 | 270篇 |
2013年 | 567篇 |
2012年 | 353篇 |
2011年 | 462篇 |
2010年 | 313篇 |
2009年 | 339篇 |
2008年 | 373篇 |
2007年 | 364篇 |
2006年 | 300篇 |
2005年 | 310篇 |
2004年 | 334篇 |
2003年 | 296篇 |
2002年 | 235篇 |
2001年 | 161篇 |
2000年 | 127篇 |
1999年 | 101篇 |
1998年 | 88篇 |
1997年 | 86篇 |
1996年 | 78篇 |
1995年 | 100篇 |
1994年 | 91篇 |
1993年 | 73篇 |
1992年 | 67篇 |
1991年 | 55篇 |
1990年 | 44篇 |
1989年 | 47篇 |
1988年 | 35篇 |
1987年 | 49篇 |
1986年 | 48篇 |
1985年 | 49篇 |
1984年 | 54篇 |
1983年 | 55篇 |
1982年 | 57篇 |
1981年 | 50篇 |
1980年 | 32篇 |
1979年 | 23篇 |
1978年 | 31篇 |
1977年 | 20篇 |
1976年 | 13篇 |
1975年 | 10篇 |
1971年 | 10篇 |
排序方式: 共有7776条查询结果,搜索用时 250 毫秒
91.
The density of red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae), necessary to limit boll weevil abundance, Anthonomus grandis Boheman (Coleoptera: Curculionidae), below the action level was determined. An inaction level of 0.4 fire ants per shake bucket sample (i.e., four ants per 10 plant terminals) will provide boll weevil control approximately 90% of the time. A dynamic inaction level is also provided. Total mortality of boll weevil developmental stages including eggs through teneral adults averaged 97.9%. Of 100 boll weevil eggs deposited in cotton squares (flower buds), an average of two adults survive of which about half are female. Thus, the net replacement rate per generation (Ro is 1.0 which, in this case, indicates a stable boll weevil population. 相似文献
92.
The economics of climate change in agriculture 总被引:1,自引:0,他引:1
Zilberman David Liu Xuemei Roland-Holst David Sunding David 《Mitigation and Adaptation Strategies for Global Change》2004,9(4):365-382
This paper presents a conceptual frameworkof the impact of climate change onagriculture. It assumes that climatechange will result in a fertilizationeffect and a shift of agro-ecologicalconditions away from the Equator towardsthe Poles. The agro-ecological shift islikely to reduce yield because of reducedacreage and the fertilization effect willincrease yield. The aggregate effectdepends on whichever of the two dominates. The overall effect of climate change may beless significant than its distributionaleffects and the results are consistentwith previous empirical studies. Theimpact of climate change depends on itspace. Faster changes in climate willresult in higher cost. The assessment ofthe cost has to consider that climatechange is a dynamic phenomenon that mayrequire continuous adjustment. Environmental regulation that emphasizesconservation may increase cost ofadjustment and environmental policiesshould emphasize adaptation andflexibility. 相似文献
93.
M.?A.?de?FigueiredoEmail author D.?M.?Reiner H.?J.?Herzog 《Mitigation and Adaptation Strategies for Global Change》2005,10(4):647-657
This paper examines how legal standards of liability may apply to geologic carbon storage. The liability regime governing
geologic carbon storage will shape the technology's cost-effectiveness and overall attractiveness. We classify potential sources
of liability into operational, in situ, and climate liability. As a first step, we explore in situ liability in the United States. After summarizing legal standards of liability including negligence, breach of implied warranty,
strict liability, and product liability, we discuss how liability may be addressed at the level of the federal government,
state government, industry, and the firm. Finally, we address the implications of judicial treatment of liability for carbon
storage, including the apportionment of liability and the adequacy of current regulations. 相似文献
94.
The Science of Nature - Because of the sudden rise in primary-energy costs and the rapid inflation of plants which are used for the conversion of primary to secondary energy, the storage of energy,... 相似文献
95.
Linda?Anderson-BerryEmail author David?King 《Mitigation and Adaptation Strategies for Global Change》2005,10(3):367-392
Community mitigation of hazard impact requires hazard knowledge and preparedness on the part of the members of diverse and
complex communities. Longitudinal research in the tropical cyclone prone north of Australia has gathered extensive datasets
on community awareness, preparedness and knowledge, in order to contribute to education campaigns and mitigation strategies.
Data have been used to identify issues of vulnerability to cyclones and capacity to deal with the hazard. This has been developed
as a community vulnerability and capacity model that may be applied to diverse communities in order to assess levels of capability
to mitigate and deal with the cyclone hazard. The model is presented here in a simplified form as its development is evolving
and ongoing. 相似文献
96.
Maguelone G. Forest Hervé Bétuel Philippe Couillin André Boué Michel David Daniel Floret René Francois Pierre Guibaud Henri Plauchu Raphaël Rappaport 《黑龙江环境通报》1981,1(3):197-207
Amniotic fluid (AF) levels of 17-hydroxyprogesterone (17OHP) and testosterone (T) were determined at 16–17 weeks in 17 pregnancies at risk for CAH and results compared to 75 normal controls. The fetus was predicted to be unaffected in 12 cases on the findings of normal AF levels of both 17OHP and T and the latter allowed a correct prediction of fetal sex in all instances. HLA typing confirmed normality in 12 cases revealing 5 carriers, 5 homozygous normal and 2 indeterminate. Steroid levels of the 2 groups were similar. Three fetuses were predicted to be CAH affected on unambiguously high levels of 17OHP and T (in female only). HLA typing was in agreement, and the diagnosis was confirmed in 2 abortuses and a female newborn by physical and hormonal studies. In the last 2 cases AF levels of OHP and T were normal but HLA (A/B/C) genotypes were identical to the CAH affected siblings. Normal physical and hormonal findings in the 2 aborted fetuses would exclude the possibility of an in utero virilizing form of CAH. The discrepancy could be explained on the basis that the fetuses had an allelic form of 21-hydroxylase deficiency or on the basis of recombination (not fully tested). It is concluded that a fully informative prenatal diagnosis of CAH should not rely entirely on HLA typing but on hormonal studies. 相似文献
97.
98.
99.
Klaassien J. Ganzeveld Annechien van Hagen Martin H. van Agteren Wim de Koning Anton J. M. Schoot Uiterkamp 《Journal of Cleaner Production》1999,7(6):690
Two types of fermented organic waste (trade and industry waste and fruit and vegetable waste) were successfully used as a sole carbon source to produce poly-3-hydroxybutyrate-co-valerate (PHBV) by Ralstonia eutrophus (formerly Alcaligenes eutrophus) via oxygen limitation.The production of PHBV could be optimized by optimizing the oxygen transfer through the fermentor. Thereby, a peak concentration of 1.1 g PHBV per liter cell suspension, 40 w% of cell dry weight, was obtained at an aeration rate of 0.24 mol O2/h·kg biomass. The yield of PHBV on the fatty acid concentration in the organic waste was 0.16 g polymer/g volatile organic matter. The process obtained, compares well with the commercial production process of PHBV based on glucose. 相似文献
100.
Val A. Catanzarite MD Ph.D. David B. Schrimmer Cynthia Maida Art Mendoza 《黑龙江环境通报》1995,15(3):229-235
The sinusoidal fetal heart rate pattern has been described in association with severe fetal anaemia, with fetal hypoxaemia, and with the administration of parenteral narcotics. Here, we report a case of decreased fetal movement in which a sinusoidal tracing was recorded. The sonographic diagnosis of a massive fetal intracranial haemorrhage was made. A non-interventive approach was taken and the fetus died soon after in utero. We review 28 previous cases in which the prenatal sonographic diagnosis of fetal intracranial haemorrhage was made, including the underlying maternal and fetal factors and neonatal outcomes. We propose that the sinusoidal tracing in this case was due to the intracranial bleed and suggest that fetal intracranial haemorrhage be considered in the sonographic evaluation of the fetus with a sinusoidal pattern. 相似文献