全文获取类型
收费全文 | 1390篇 |
免费 | 105篇 |
国内免费 | 364篇 |
专业分类
安全科学 | 266篇 |
废物处理 | 7篇 |
环保管理 | 111篇 |
综合类 | 734篇 |
基础理论 | 419篇 |
环境理论 | 1篇 |
污染及防治 | 95篇 |
评价与监测 | 41篇 |
社会与环境 | 137篇 |
灾害及防治 | 48篇 |
出版年
2024年 | 7篇 |
2023年 | 23篇 |
2022年 | 47篇 |
2021年 | 70篇 |
2020年 | 66篇 |
2019年 | 60篇 |
2018年 | 62篇 |
2017年 | 70篇 |
2016年 | 78篇 |
2015年 | 82篇 |
2014年 | 72篇 |
2013年 | 184篇 |
2012年 | 85篇 |
2011年 | 99篇 |
2010年 | 85篇 |
2009年 | 70篇 |
2008年 | 69篇 |
2007年 | 81篇 |
2006年 | 75篇 |
2005年 | 58篇 |
2004年 | 49篇 |
2003年 | 54篇 |
2002年 | 44篇 |
2001年 | 39篇 |
2000年 | 33篇 |
1999年 | 32篇 |
1998年 | 19篇 |
1997年 | 13篇 |
1996年 | 8篇 |
1995年 | 36篇 |
1994年 | 25篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1859条查询结果,搜索用时 843 毫秒
761.
浅谈环境噪声的危害与控制 总被引:2,自引:0,他引:2
通过了解噪声的来源;具体分析了噪声对人体的危害,不同的噪声,级别不同,对人体的健康影响程度也不同,尤其是长期接触噪声的工作人员。如何有效地防治噪声,从噪声源、传播途径及个人防护方面进行了具体的分析。 相似文献
762.
环境噪声污染对人体健康的影响 总被引:5,自引:0,他引:5
环境噪声污染污染对人体健康危害十分严重,除影响听力外,还可能引发神经,心血管,消化,内分泌及免疫系统疾病,且对视力,优生优育均有不同程度影响。加强环境噪声污染的防治,对于保障人民健康有重要意义。 相似文献
763.
764.
Esther Berry David A. Aitken Jennifer A. Crossley James N. Macri J. Michael Connor 《黑龙江环境通报》1995,15(6):555-565
The aim of this study was to determine the maternal population, pregnancy, serum alpha-fetoprotein (AFP) and free β subunit of human chorionic gonadotrophin (FβhCG) parameters in a large series of women attending prenatal clinics before 15 weeks' gestation and to assess the practical problems of population screening for Down's syndrome in the first trimester using these markers. Serum samples were collected from 8600 women attending prenatal clinic booking visits. Maternal serum AFP and FβhCG medians were calculated for each day of gestation (49–104 days), using both dates and ultrasound estimates of gestation. The effects of maternal weight, twin pregnancies, and threatened abortion on AFP and FβhCG levels were analysed. The median age of the population was 27.1 years and the median weight 62.1 kg. Twenty-six per cent of samples were collected before 70 days and 50 per cent before 78 days' gestation. Eighty-nine per cent of all samples had gestational estimates by dates, 60 per cent by ultrasound and 52 per cent by both dates and ultrasound. The AFP median was 5 kU/1 at 49 days, 5.9 kU/1 at 70 days, and 17.9 kU/1 at 100 days. The peak median FβhCG level was 66.4 ng/ml at 64 days, falling to 20.6 ng/ml at 100 days' gestation. Both AFP and FβhCG levels showed log Gaussian distributions but the standard deviation for AFP was 20 per cent greater than that found in the second trimester. AFP and FβhCG levels showed an inverse relationship with maternal weight and were increased in twin pregnancies (1.68 and 1.97 multiples of the median, respectively). AFP and FβhCG can be readily measured in a large screening population in the first trimester. Down's syndrome screening protocols based on these markers could be refined by the use of gestations in individual days but AFP is likely to be a less effective marker and detection rates are likely to be lower than in the second trimester. To realize the potential of first-trimester screening, more women should be encouraged to attend the prenatal clinic in early pregnancy and ultrasound dating should be carried out for all pregnancies at this stage. 相似文献
765.
Gao Yan-chun 《环境科学学报(英文版)》1998,10(3)
The Yellow River, or Huanghe, is one of the most important river in China. It is the major water resources for north and northwest China. Since 1972, the Yellow River's dry-up has occurred frequently and become even more year by year. Except the huge loss to social life and economic development, the Yellow River's dry-up brings about great impacts to eco-environment. This paper analyzed the reasons and impacts from multi-aspect: effects of climate change, influence of human activities and impacts to delta's eco-environment, aquatic life resources, agricultural eco-environment, water pollution and flood prevention as well. 相似文献
766.
767.
768.
John CairnsJr. 《环境科学学报(英文版)》1990,2(2):1-17
An effective plan for global ecosystem management must be developed in the next 10 or 20 years. Awareness of the need has recently emerged, but still no integrated resource management system is universally accepted. A fragmented management approach has not been effective. Any successful course of action must be based on three assumptions: (1) that science can determine how ecosystems function, (2) once this is known, the social/political system will be able to protect ecosystems to the extent needed for the survival of human society, and (3) reality will take precedence over political expediency because Mother Nature cannot be fooled. This discussion focuses on the transition from awareness to taking effective action. 相似文献
769.
为了探讨二氧化硫(SO2)对哺乳类细胞的毒性作用及其防护.以SO2体内衍生物-亚硫酸盐和亚硫酸氢盐(分子比为3∶1)及抗坏血酸(维生素C,Vc)单独或同时处理人血红细胞,并测定红细胞过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性及脂质过氧化(LPO)水平.结果表明,SO2体内衍生物单独处理后,CAT和SOD活性均显著甚至极显著降低,而LPO水平均极显著升高.Vc单独处理后,CAT及SOD活性均有所升高,但差异不显著;而LPO水平除Vc为0.05 mmol·L-1剂量组外,其余各组均极显著降低.0.1 mmol·L-1Vc和不同剂量SO2衍生物共同处理后,Vc使各组CAT、SOD活性均有升高,且Vc也降低了SO2衍生物引起的人血红细胞LPO水平.由此认为,SO2体内衍生物可以使人血红细胞中CAT和SOD的活性降低、LPO水平增高,Vc可起到一定防护作用. 相似文献
770.
介绍了人居环境的定义,并根据全面性、以人为本、可操作性、相对独立性的原则选取评价指标和构建指标体系。采用层次分析法对各指标和子系统赋予不同的权重,利用综合加权求和的方法得出该生态示范区的社会经济,基础设施和公共服务设施,生态环境以及人居环境在1999年和2000年的综合评价指数,对比人居环境1999年和2000年的评价指数,从而得出南充城市人居环境的指数在增大,状况是在不断改善,并从不同的角度给南充城市人居环境建设提出了一些建议,比如:园地制宜,采用多种投资方式加快城市基础设施和公共服务设施建设;优化城市布局,改善能源结构,加大环境治理投资,改善生态环境;加大宣传力度,提高城市可持续管理意识;坚持以人为本,搞好城市人居环境的规划和设计改善措施。 相似文献