全文获取类型
收费全文 | 3757篇 |
免费 | 46篇 |
国内免费 | 39篇 |
专业分类
安全科学 | 103篇 |
废物处理 | 138篇 |
环保管理 | 555篇 |
综合类 | 771篇 |
基础理论 | 804篇 |
环境理论 | 6篇 |
污染及防治 | 1004篇 |
评价与监测 | 242篇 |
社会与环境 | 199篇 |
灾害及防治 | 20篇 |
出版年
2023年 | 37篇 |
2022年 | 33篇 |
2021年 | 58篇 |
2020年 | 47篇 |
2019年 | 52篇 |
2018年 | 91篇 |
2017年 | 99篇 |
2016年 | 109篇 |
2015年 | 125篇 |
2014年 | 129篇 |
2013年 | 217篇 |
2012年 | 157篇 |
2011年 | 231篇 |
2010年 | 177篇 |
2009年 | 204篇 |
2008年 | 190篇 |
2007年 | 215篇 |
2006年 | 168篇 |
2005年 | 136篇 |
2004年 | 154篇 |
2003年 | 114篇 |
2002年 | 151篇 |
2001年 | 102篇 |
2000年 | 60篇 |
1999年 | 38篇 |
1998年 | 37篇 |
1997年 | 49篇 |
1996年 | 40篇 |
1995年 | 55篇 |
1994年 | 48篇 |
1993年 | 21篇 |
1992年 | 30篇 |
1991年 | 40篇 |
1990年 | 26篇 |
1989年 | 31篇 |
1988年 | 25篇 |
1987年 | 16篇 |
1986年 | 16篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1983年 | 15篇 |
1982年 | 23篇 |
1981年 | 21篇 |
1980年 | 11篇 |
1979年 | 22篇 |
1978年 | 10篇 |
1977年 | 11篇 |
1976年 | 10篇 |
1960年 | 9篇 |
1954年 | 12篇 |
排序方式: 共有3842条查询结果,搜索用时 22 毫秒
31.
32.
33.
Pesticide use in agriculture can cause undesirable effects on humans and the natural environment. One of the objectives of integrated agriculture is the elimination or reduction of possible sources of environmental pollution such as pesticides. To achieve this objective, farmers need a method to assist them in estimating the environmental impact of pesticide use. This paper addresses a two-part question: what factors should be taken into consideration to assess pesticide environmental impact, and how can impact be quantified? As the environmental impact of a pesticide depends on its dispersion in the environment and on its toxicological properties, the literature on these topics is reviewed to address the first part of the question. To address the second part of the question, six recent approaches to assess the impact of pesticides on the environment are compared regarding choice, transformation and aggregation of input parameters. The use of simulation models to assess environmental impact is discussed. 相似文献
34.
The Science of Nature - 相似文献
35.
Emanuela Terzian Jillian Boreham Howard S. Cuckle Nicholas J. Wald Martin Bobrow Richard Lindenbaum A. C. Turnbull 《黑龙江环境通报》1985,5(6):401-414
A survey was conducted of the results of mid-trimester diagnostic amniocenteses in the Oxford Region from 1974 to 1981. The survey used data relating to all 4357 singleton pregnancies in which an amniocentesis was performed during this period. Follow-up information on outcome was obtained in respect of 4284 (98 per cent) pregnancies. A cell culture to determine karyotype and an alpha-fetoprotein determination was carried out in all cases. From 1974 to 1981 amniocenteses became increasingly common, rising from 2 to 32 per 1000 births. The most common indication for amniocentesis was a high risk of a chromosome abnormality–56 per cent of all amniocenteses. Within this group advanced maternal age was responsible for 89 per cent of the cases. The next most common indication was a high risk of a neural tube defect (37 per cent of all amniocenteses)–in 1974 a raised maternal serum alpha-fetoprotein level accounted for only 4 per cent of these; by 1981 this had risen to 67 per cent. There were seven false-positive and 132 true-positive diagnoses of neural tube defect; since 1981, with the introduction of amniotic fluid acetylocholinesterase determination as a secondary diagnostic test for neural tube defects, there have been no further false-positive diagnoses. In 1981 76 per cent of women aged 35 years or more did not have an amniocentesis. It is not known to what extent this was due to not offering women in this age group amniocentesis or to women not accepting such an offer. 相似文献
36.
37.
38.
39.
40.
R. G. Tiessen A. M. W. van Elsacker-Niele Chr. Vermeij-Keers D. Oepkes J. van Roosmalen M. C. B. Gorsira 《黑龙江环境通报》1994,14(3):173-176
A fetus with multiple structural defects was seen at prenatal ultrasound examination. After termination of the pregnancy a bilateral cleft lip, alveolus, and palate; micrognathia; and webbed joints were seen. Fetal tissues showed indications of infection, intranuclear inclusion bodies, chronic stress, haemolysis, arterial wall damage, and profuse haemorrhage. Parvovirus B19 DNA was detected in fetal tissues by dot hybridization after polymerase chain reaction. The possibility of parvovirus B19 infection leading to congenital malformations is discussed. 相似文献