全文获取类型
收费全文 | 14727篇 |
免费 | 101篇 |
国内免费 | 174篇 |
专业分类
安全科学 | 354篇 |
废物处理 | 596篇 |
环保管理 | 1581篇 |
综合类 | 3397篇 |
基础理论 | 3460篇 |
环境理论 | 6篇 |
污染及防治 | 3656篇 |
评价与监测 | 1110篇 |
社会与环境 | 772篇 |
灾害及防治 | 70篇 |
出版年
2022年 | 128篇 |
2021年 | 108篇 |
2019年 | 102篇 |
2018年 | 195篇 |
2017年 | 207篇 |
2016年 | 307篇 |
2015年 | 233篇 |
2014年 | 404篇 |
2013年 | 1044篇 |
2012年 | 458篇 |
2011年 | 601篇 |
2010年 | 478篇 |
2009年 | 536篇 |
2008年 | 579篇 |
2007年 | 597篇 |
2006年 | 560篇 |
2005年 | 513篇 |
2004年 | 458篇 |
2003年 | 469篇 |
2002年 | 443篇 |
2001年 | 603篇 |
2000年 | 378篇 |
1999年 | 277篇 |
1998年 | 155篇 |
1997年 | 169篇 |
1996年 | 181篇 |
1995年 | 195篇 |
1994年 | 187篇 |
1993年 | 137篇 |
1992年 | 166篇 |
1991年 | 175篇 |
1990年 | 169篇 |
1989年 | 146篇 |
1988年 | 158篇 |
1987年 | 99篇 |
1986年 | 129篇 |
1985年 | 130篇 |
1984年 | 123篇 |
1983年 | 120篇 |
1982年 | 121篇 |
1981年 | 121篇 |
1980年 | 89篇 |
1979年 | 101篇 |
1978年 | 102篇 |
1976年 | 92篇 |
1974年 | 105篇 |
1972年 | 89篇 |
1967年 | 101篇 |
1966年 | 90篇 |
1964年 | 99篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
241.
Diana W. Bianchi MD Gretchen K. Zickwolf Melissa C. Yih Alan F. Flint Ossie H. Geifman Marlena S. Erikson John M. Williams 《黑龙江环境通报》1993,13(4):293-300
Fetal nucleated erythrocytes (NRBC) in maternal blood are a non-invasive source of fetal DNA for prenatal genetic screening. We compared the effectiveness of three monoclonal antibodies for the separation of fetal cells from maternal blood by flow sorting. Mononuclear blood cells from 49 healthy pregnant women were incubated with antibody to CD 71, CD 36, and/or glycophorin A (GPA), employed singly or in combination with each other. These monoclonal antibodies recognize surface antigens on haematopoietic precursor cells. Successful isolation of fetal cells was defined as detection of Y chromosomal sequences in maternal blood from women carrying male fetuses, with absence of Y sequences when female fetuses were carried. Thus, gender prediction accuracy was used as a measure of fetal cell separation. Using anti-CD 71 to isolate fetal cells, gender prediction was 57 per cent correct; with anti-CD 36, it was 88 per cent correct. Anti-GPA, an erythrocyte-specific antigen, used alone or in combination with anti-CD 71 or 36, improved gender prediction to 100 per cent. We conclude that antibody to GPA improves the retrieval of fetal NRBC from maternal blood, permitting genetic analysis by the polymerase chain reaction. 相似文献
242.
Maya Thangavelu PhD Eugene Pergament Rafael Espinosa Iii Stefan K. Bohlander 《黑龙江环境通报》1994,14(7):583-588
We characterized by microdissection and fluorescence in situ hybridization (FISH) two marker chromosomes: (1) a de novo, acrocentric marker chromosome detected in 88 per cent of the amniotic fluid cells of one of two physically and developmentally normal twins; and (2) a metacentric marker chromosome present in a phenotypically normal female. Analysis of FISH probes developed from the marker chromosomes indicated that the marker chromosomes in cases 1 and 2 were del(14)(q11) and a derivative chromosome from a Robertsonian translocation, respectively. Microdissection in combination with FISH may prove to be a valuable technique in determining the chromosomal origin of de novo marker chromosomes and unbalanced structural rearrangements detected during prenatal diagnosis. 相似文献
243.
244.
245.
246.
247.
248.
249.
Polyacetylene is presented as the prototype of a metallic conducting polymer. The concepts of one-dimensional metal physics are illustrated and special attention is drawn to a structural defect called “soliton”. Electrical, magnetic, and optical experiments connected with solitons are discussed. The authors' opinion is expressed that present experimental results do not yet furnish strong evidence for the existence of solitons in polyacetylene, but that the soliton idea is a fruitful stimulus for further investigations and novel applications. 相似文献
250.