全文获取类型
收费全文 | 43215篇 |
免费 | 832篇 |
国内免费 | 5677篇 |
专业分类
安全科学 | 1726篇 |
废物处理 | 1964篇 |
环保管理 | 5258篇 |
综合类 | 13413篇 |
基础理论 | 9872篇 |
环境理论 | 12篇 |
污染及防治 | 12968篇 |
评价与监测 | 2129篇 |
社会与环境 | 1585篇 |
灾害及防治 | 797篇 |
出版年
2023年 | 337篇 |
2022年 | 834篇 |
2021年 | 748篇 |
2020年 | 542篇 |
2019年 | 620篇 |
2018年 | 858篇 |
2017年 | 983篇 |
2016年 | 1229篇 |
2015年 | 1305篇 |
2014年 | 1813篇 |
2013年 | 3908篇 |
2012年 | 2077篇 |
2011年 | 2444篇 |
2010年 | 1811篇 |
2009年 | 1969篇 |
2008年 | 2163篇 |
2007年 | 2140篇 |
2006年 | 1900篇 |
2005年 | 1493篇 |
2004年 | 1312篇 |
2003年 | 1430篇 |
2002年 | 1325篇 |
2001年 | 1464篇 |
2000年 | 1195篇 |
1999年 | 955篇 |
1998年 | 774篇 |
1997年 | 690篇 |
1996年 | 740篇 |
1995年 | 699篇 |
1994年 | 643篇 |
1993年 | 560篇 |
1992年 | 499篇 |
1991年 | 430篇 |
1990年 | 449篇 |
1989年 | 403篇 |
1988年 | 371篇 |
1987年 | 338篇 |
1986年 | 300篇 |
1985年 | 306篇 |
1984年 | 311篇 |
1983年 | 322篇 |
1982年 | 313篇 |
1981年 | 313篇 |
1980年 | 266篇 |
1979年 | 284篇 |
1978年 | 237篇 |
1977年 | 203篇 |
1976年 | 206篇 |
1973年 | 202篇 |
1972年 | 202篇 |
排序方式: 共有10000条查询结果,搜索用时 656 毫秒
361.
362.
363.
364.
中国污水资源化问题及对策 总被引:8,自引:0,他引:8
分析了我国水资源状况、水质现状和污染源治理情况,找出污水资源化存在的七个问题,提出六大对策,以便充分利用有限的水资源,减轻水体污染程度,促进国民经济持续、健康、稳定发展. 相似文献
365.
感光胶片废水的水解酸化—好氧处理工艺试验 总被引:1,自引:0,他引:1
对感光胶片有机生产废水处理工艺进行了方法采用水解酸化-好氧串联工艺和传统活性污泥法两种方法并进行对照。结果经水解酸化处理,废水的BOD5/CODcr可提高至0.54-0.56,平均增加了17%左右,证实了水解酸化菌在该工艺条件下具有搞高效片废水可生化性的功能。 相似文献
366.
Mary C. Phelan Ph.D. Robert A. Saul Thompson A. Gailey Jr Steven A. Skinner 《黑龙江环境通报》1995,15(3):274-277
Mosaicism for the Wolf-Hirschhorn syndrome, del(4)(p16), is extremely rare and has not been reported in association with a numerical chromosome abnormality. We report the prenatal diagnosis of mosaic del(4)(p16) and non-mosaic trisomy 21 in a 16-week female fetus. The pregnancy ended in spontaneous abortion at 34 weeks secondary to fetal demise. The fetus had features of both 4p – and trisomy 21. 相似文献
367.
Forty-two open neural tube defects (NTDs) were identified in our series of 7440 amniocenteses tested between 11 and 15 weeks of gestation. Using a cut-off of ≥2.0 MOM, the detection rate for open NTDs was 95 per cent; 100 per cent each for anencephaly and spina bifida; and 78 per cent for encephalocele. Two encephaloceles had AFP levels less than 2.0 MOM and negative AChEs. Thirty-four (81 per cent) of these NTDs were tested between 13 and 15 weeks and 8 (19 per cent) before 13 weeks. There were 0.6 per cent false positives by AFP (excluding serious abnormalities and fetal death) and 0.1 per cent after AChE. The likelihood of an open NTD after an elevated AFP (≥2.0 MOM) was 24 and 77 per cent for any serious abnormality. These results, when combined with an earlier study, indicate that amniotic fluid AFP appears to be as sensitive a test for open NTDs between 13 and 15 weeks as between 16 and 20 weeks. Additional experience is necessary to determine this before 13 weeks. 相似文献
368.
369.
Dr. R. J. A. Wanders R. B. H. Schutgens H. van den Bosch J. M. Tager W. J. Kleijer 《黑龙江环境通报》1991,11(4):253-261
In recent years, an increasing number of inherited diseases in man have been recognized in which there is an impairment in the peroxisomal β-oxidation of very-long-chain fatty acids. In general, these disorders are associated with severe neurological and physical abnormalities and death within the first years of life. In this paper we describe our experience with regard to the prenatal diagnosis of a number of different inborn errors of peroxisomal β-oxidation. Eleven pregnancies at risk were monitored by measuring very-long-chain fatty acid levels as well as very-long-chain fatty acid β-oxidation in cultured chorionic villous fibroblasts and/or amniotic fluid cells. Five affected fetuses were identified. It is concluded that prenatal diagnosis in this group of diseases can be done reliably using cultured chorionic villous fibroblasts or amniotic fluid cells. 相似文献
370.