全文获取类型
收费全文 | 2309篇 |
免费 | 45篇 |
国内免费 | 389篇 |
专业分类
安全科学 | 107篇 |
废物处理 | 133篇 |
环保管理 | 213篇 |
综合类 | 711篇 |
基础理论 | 514篇 |
环境理论 | 1篇 |
污染及防治 | 708篇 |
评价与监测 | 135篇 |
社会与环境 | 151篇 |
灾害及防治 | 70篇 |
出版年
2023年 | 40篇 |
2022年 | 99篇 |
2021年 | 47篇 |
2020年 | 35篇 |
2019年 | 40篇 |
2018年 | 88篇 |
2017年 | 65篇 |
2016年 | 70篇 |
2015年 | 107篇 |
2014年 | 102篇 |
2013年 | 210篇 |
2012年 | 112篇 |
2011年 | 165篇 |
2010年 | 141篇 |
2009年 | 122篇 |
2008年 | 140篇 |
2007年 | 110篇 |
2006年 | 93篇 |
2005年 | 92篇 |
2004年 | 107篇 |
2003年 | 90篇 |
2002年 | 68篇 |
2001年 | 122篇 |
2000年 | 62篇 |
1999年 | 50篇 |
1998年 | 36篇 |
1997年 | 24篇 |
1996年 | 24篇 |
1995年 | 41篇 |
1994年 | 16篇 |
1993年 | 14篇 |
1992年 | 18篇 |
1991年 | 12篇 |
1990年 | 12篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 7篇 |
1985年 | 8篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1980年 | 6篇 |
1975年 | 8篇 |
1974年 | 10篇 |
1973年 | 7篇 |
1972年 | 12篇 |
1966年 | 5篇 |
1965年 | 5篇 |
1959年 | 5篇 |
1957年 | 5篇 |
排序方式: 共有2743条查询结果,搜索用时 46 毫秒
31.
32.
Farideh Z. Bischoff PhD Dorothy E. Lewis Joe Leigh Simpson Dianne D. Nguyen Jeffrey Scott Wendy Schober Sarah Murrell Sherman Elias 《黑龙江环境通报》1995,15(12):1182-1184
Recovering and analysing fetal erythrocytes from maternal blood is being pursued for non-invasive prenatal genetic diagnosis. We report the observation of 46, XY/47, XXY mosaicism in fetal cells from a woman whose first-trimester chorionic villus sampling (CVS) initially showed only 46, XY. Only after exhaustive (500 cells) analysis were four XXY cells found in cultured villi. 相似文献
33.
34.
The nature of the cosmic redshift is one of the most fundamental questions in modern science. Hubble's discovery of the apparent Expansion of the Universe is derived from observations on a small number of galaxies at very low redshifts. Today, quasar redshifts have a range more than 1000 times greater than those in Hubble's sample, and represent more than 100 times as many objects. A recent comprehensive compilation of published measurements provides the basis for a study indicating that quasar observations are not in good agreement with the original predictions of the Expanding Universe theory, but are well fit by the predictions of an alternative theory having fewer adjustable parameters. 相似文献
35.
36.
37.
38.
39.
40.
Urinary tract anomalies are common. Prenatal diagnosis is important and enables either special obstetric management or termination of pregnancy and probably in the future, intrauterine intervention. Transvaginal sonography (TVS) allows visualization of the normal and anomalous fetal urinary tract at an early stage. One thousand nine hundred and forty women were examined via TVS at an early stage of pregnancy between 10 and 16 weeks from the last menstrual period (LMP) and 35 anomalies (1·8 per cent) were clearly identified: 29 cases of low urinary tract obstruction, 2 cases of multicystic dysplastic kidney, 2 cases of polycystic kidney (infantile type), 1 case of double collecting system, and 1 case of horseshoe kidney. Potter syndrome could be ruled out in three patients who had delivered fetuses suffering from this anomaly in previous pregnancies. The concise and early identification of anomalies makes TVS an important aid in the hands of the obstetrician, ultrasonographer, and neonatologist. 相似文献