全文获取类型
收费全文 | 4935篇 |
免费 | 106篇 |
国内免费 | 74篇 |
专业分类
安全科学 | 233篇 |
废物处理 | 244篇 |
环保管理 | 1296篇 |
综合类 | 422篇 |
基础理论 | 1152篇 |
环境理论 | 5篇 |
污染及防治 | 1181篇 |
评价与监测 | 345篇 |
社会与环境 | 187篇 |
灾害及防治 | 50篇 |
出版年
2023年 | 22篇 |
2022年 | 21篇 |
2021年 | 47篇 |
2020年 | 32篇 |
2019年 | 60篇 |
2018年 | 72篇 |
2017年 | 93篇 |
2016年 | 117篇 |
2015年 | 117篇 |
2014年 | 112篇 |
2013年 | 565篇 |
2012年 | 181篇 |
2011年 | 259篇 |
2010年 | 196篇 |
2009年 | 189篇 |
2008年 | 272篇 |
2007年 | 272篇 |
2006年 | 246篇 |
2005年 | 172篇 |
2004年 | 189篇 |
2003年 | 192篇 |
2002年 | 175篇 |
2001年 | 85篇 |
2000年 | 111篇 |
1999年 | 100篇 |
1998年 | 80篇 |
1997年 | 65篇 |
1996年 | 76篇 |
1995年 | 75篇 |
1994年 | 64篇 |
1993年 | 68篇 |
1992年 | 74篇 |
1991年 | 46篇 |
1990年 | 53篇 |
1989年 | 46篇 |
1988年 | 38篇 |
1987年 | 42篇 |
1986年 | 44篇 |
1985年 | 42篇 |
1984年 | 47篇 |
1983年 | 50篇 |
1982年 | 41篇 |
1981年 | 55篇 |
1980年 | 48篇 |
1979年 | 23篇 |
1978年 | 24篇 |
1977年 | 21篇 |
1976年 | 13篇 |
1975年 | 15篇 |
1971年 | 13篇 |
排序方式: 共有5115条查询结果,搜索用时 218 毫秒
51.
The de-O-sulphation of α-linked glucosamine-6-sulphate residues in heparan sulphate requires a specific sulphatase, glucosamine-6-sulphatase, which has been shown to be deficient in tissues of Sanfilippo D, or mucopolysaccharidosis type IIID (MPS IIID), patients. MPS IIID fibroblasts cultured in Basal Eagle's medium supplemented with either fetal calf serum or heat-inactivated fetal calf serum, MDCB or Ultraserg media had residual glucosarnine-6-sulphatase activities towards a heparin-derived trisaccharide substrate, O-(α-N-acetylglucosamine-6-sulphate)-(1→4)-L -O-(α-iduronic acid-2-sulphate)-(1→4)-D -O-2,5-anhydro [1-3H]mannitol-6-sulphate, GlcNAc6S-IdoA2S-anM6S, which were less than 1 per cent of the normal range for fibroblasts cultured in Basal Eagle's medium supplemented with fetal calf serum. However, the glucosamine-6-sulphatase activities of MPS IIID fibroblasts grown in Chang's medium were similar to the activities in normal control fibroblasts which were cultured in Basal Eagle's medium. These results indicate that caution is required for prenatal diagnosis of MPS IIID patients using chorionic villi or amniotic cells cultured in Chang's medium. 相似文献
52.
A de novo paracentric inversion of chromosome 11 identified through antenatal diagnosis is described along with long-term follow-up information on the child and discussion of reported experiences with de novo inversions. 相似文献
53.
Flamos Alexandros Anagnostopoulos Konstantinos Askounis Dimitris Psarras John Butzengeiger Sonja van der Gaast Wytze 《Mitigation and Adaptation Strategies for Global Change》2004,9(2):103-120
This paper presentse-SEREM (Smart Emission ReductionEstimation Manual), a cost-free, easilyaccessed and updated, web-based manual forestimating emission reductions from Joint Implementation (JI) andClean Development Mechanism (CDM) projects. e-SEREM's main functions arethe selection of a benchmark for a specificproject type in the power or heat sectorand the calculation of the annual andcumulative emission reductions accrued bythis project for its crediting lifetime.e-SEREM was developed in order to test itsapplicability and practicality in assistingproject developers and evaluators toelaborate baselines easily and calculatethe emission credits earned by candidate JIor CDM projects hosted in several countries. 相似文献
54.
55.
John Gregory 《环境科学学报(英文版)》1999,11(3):328-333
1 IntroductionParticlesinnaturalwatersareoftentoosmalltobeeffectivelyremovedbytheseseparationtechniques.Theprocessofcoagulation/flocculationcausesfineparticlestoaggregateintolargerunits(flocs)whichcanbemoreeasilyseparated.Inwatertreatmentsaltsofalumi… 相似文献
56.
Industrial ecology: a new field or only a metaphor? 总被引:1,自引:0,他引:1
In the 10 years since industrial ecology first became a topic of academic interest, it has grown as a field of inquiry and has produced a community of practice in several sectors including academia, business, and government. Even as the shape of industrial ecology becomes clearer, questions remain as to its lasting power beyond the metaphor that gave it its distinctiveness. This paper examines the development of industrial ecology and assesses its progress towards becoming a field of academic inquiry. And, in a related analysis, I look at the progress industrial ecology has made in establishing itself as an institutional (cultural) basis for action in the above sectors. Ideas like industrial ecology must become institutionalized if they are to have much effect on the reality of everyday activities. 相似文献
57.
CLIMATE CHANGE AND NATURAL HAZARDS IN NORTHERN CANADA: INTEGRATING INDIGENOUS PERSPECTIVES WITH GOVERNMENT POLICY 总被引:1,自引:0,他引:1
John?NewtonEmail author C.?D.?James?Paci Aynslie?Ogden 《Mitigation and Adaptation Strategies for Global Change》2005,10(3):541-571
A study of the relationship between natural hazards and climate change in the international context provides the background
for a discussion of the expected changes. In the context of this global discussion, this paper reviews the current perspectives
of those natural hazards that are likely to be influenced by climate change, using northern Canada as a regional case study.
The northern implications of the United Nations Framework Convention on Climate Change are examined, including the status
of climate change action by the northern territorial governments, the evolving role of indigenous people, and the responsibility
for climate change impacts. The difficulties surrounding natural hazards research in remote locations, and the approaches
of indigenous people to natural hazards are then presented. The paper concludes with a suggested policy approach for climate
change and natural hazards in northern Canada, underscoring the need for more comprehensive adaptive strategies to complement
the current tendency to focus on the mitigation of greenhouse gases produced in this region. 相似文献
58.
Hemolymph sodium, potassium and calcium concentrations were determined in crayfish (Orconectes propinquus) exposed to (203)HgCl(2) mixed with food to a concentration of 1 microg Hg g(-1). Dummy-fed animals were exposed to Hg-dosed food wrapped in dialysis tubing to control for mercury reaching the animals via leaching from food to water. Hemolymph analyses were made following 14-day Hg exposures and again after a further 21-day 'depuration' period during which all animals were fed Hg-free food. After 14 days, the mercury reached a concentration of 0.175 microg g(-1) in the hepatopancreas and approximately half this level in the gills of Hg-fed animals. No depuration occurred from the hepatopancreas although the gills lost approximately two-thirds of their labelled mercury during the depuration period. Hemolymph sodium concentrations in Hg-exposed crayfish, both fed and dummy-fed, after 14 days were significantly lower than in Hg-free controls and remained low following the 21-day depuration period. Hemolymph calcium concentrations were lower in Hg-fed animals than in dummy-fed and control animals after 14 days although calcium levels rose in all treatments after 35 days. This may have been due to the incidence of pre-molt animals in all experimental groups, although the relationship between this and mercury exposure was not established unequivocally. Hemolymph potassium levels showed no differences between treatments. 相似文献
59.
60.
John H Mutti J.David Richardson 《Journal of Environmental Economics and Management》1977,4(2):135-152
This paper demonstrates empirically the gain from adopting more general equilibrium approaches in projecting the effects on domestic output and international trade of environmental controls. The suggested models include a partial equilibrium case where all industries are treated independently, an intermediate case incorporating effects in supplying industries, and general equilibrium formulations based on alternative macroeconomic conditions. U. S. data is used to evaluate these models. Under both pollutor pays and subsidy financing schemes, moving from the simplest case to the intermediate model results in quite different industry projections. Including macroeconomic factors appears particularly important in the classical setting. 相似文献