全文获取类型
收费全文 | 92881篇 |
免费 | 1230篇 |
国内免费 | 1128篇 |
专业分类
安全科学 | 3748篇 |
废物处理 | 3399篇 |
环保管理 | 14164篇 |
综合类 | 21199篇 |
基础理论 | 26665篇 |
环境理论 | 77篇 |
污染及防治 | 15747篇 |
评价与监测 | 5633篇 |
社会与环境 | 4049篇 |
灾害及防治 | 558篇 |
出版年
2022年 | 819篇 |
2021年 | 829篇 |
2020年 | 664篇 |
2019年 | 873篇 |
2018年 | 1222篇 |
2017年 | 1237篇 |
2016年 | 2232篇 |
2015年 | 1854篇 |
2014年 | 2592篇 |
2013年 | 9272篇 |
2012年 | 2284篇 |
2011年 | 2642篇 |
2010年 | 3353篇 |
2009年 | 3462篇 |
2008年 | 2173篇 |
2007年 | 2096篇 |
2006年 | 2426篇 |
2005年 | 2384篇 |
2004年 | 2685篇 |
2003年 | 2538篇 |
2002年 | 2086篇 |
2001年 | 2473篇 |
2000年 | 2101篇 |
1999年 | 1563篇 |
1998年 | 1386篇 |
1997年 | 1367篇 |
1996年 | 1504篇 |
1995年 | 1588篇 |
1994年 | 1485篇 |
1993年 | 1340篇 |
1992年 | 1338篇 |
1991年 | 1301篇 |
1990年 | 1255篇 |
1989年 | 1223篇 |
1988年 | 1062篇 |
1987年 | 998篇 |
1986年 | 998篇 |
1985年 | 1062篇 |
1984年 | 1162篇 |
1983年 | 1171篇 |
1982年 | 1178篇 |
1981年 | 1095篇 |
1980年 | 946篇 |
1979年 | 931篇 |
1978年 | 823篇 |
1977年 | 720篇 |
1976年 | 639篇 |
1974年 | 607篇 |
1973年 | 637篇 |
1972年 | 636篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
751.
Dr. Linda A. Cannizzaro Barbara K. Hecht Helen A. Bixenman Stephen Pazdziorko Robert Tamis Frederick Hecht 《黑龙江环境通报》1988,8(4):297-301
We report herein a de novo unbalanced chromosome translocation in a fetus resulting from in vitro fertilization technology. Prenatal diagnostic analysis of an amniotic fluid revealed a 46,XX,4p+ karyotype. The origin of the extra material on the short arm of chromosome 4 could not be identified by a variety of banding techniques. However, examination of fetal parts did reveal some dysmorphic features. 相似文献
752.
In vitro characteristics of human fetal cells have been investigated after chorionic villus sampling at the first trimester and amniocentesis at the second trimester of pregnancy. Light microscopy revealed heterogeneous morphology of cell types in both the chorionic villus culture and the amniotic fluid cultures. Based on the experiments performed, chorionic villus cells are more sensitive to pronase, trypsin, and versene during subculture and have a higher DNA content per single cell and release more [125I]-Beta-human chorionic gonadotropin into culture medium than those found in amniotic fluid cells. The practical applications of this study are discussed. 相似文献
753.
K. Schmetzer 《Die Naturwissenschaften》1987,74(3):136-137
754.
A Framework for Monitoring and Evaluating Carbon Mitigation by Farm Forestry Projects: Example of a Demonstration Project in Chiapas,Mexico 总被引:1,自引:0,他引:1
De Jong Ben H.J. Tipper Richard Taylor John 《Mitigation and Adaptation Strategies for Global Change》1997,2(2-3):231-246
Mitigation and Adaptation Strategies for Global Change - In Mexico an estimated 4.5 × 106ha are available for farm forestry, while up to 6.1 × 106 ha could be saved from deforestation by... 相似文献
755.
756.
757.
厦门西港海水质量对鱼卵胚胎发育畸形率的影响 总被引:3,自引:1,他引:3
以养殖场培育的花尾胡椒鲷受精卵为实验材料测试了厦门西域5个站位的表层水水样对花尾胡椒鲷受精卵的胚胎发育毒性,并运用GC-MS手段分析了水样中的美国EPA优控的16PAHs组分的含量。结果表明:3号站位(厦门市工业和生活污水主要排放口的外侧)和4号站位(厦门西港的港区)的水样对鱼卵的胚胎发育的毒性最强。8号站位(位于主航道并濒临嵩屿电厂)的水样对鱼卵胚胎发良的毒性次之,1号站位(湾口)和5号站位(内港)的水样对鱼卵的胚胎发育的毒性较小。水样中的PAHs含量分析结果表明,仅用水样中的PAHs含量不能全面地反映水样对鱼卵胚胎发育的毒性。最后,对本实验方法应用于海洋环境生物监测的有效性进行了探讨。 相似文献
758.
P. Robbins-Furman J. T. Hecht M. Rocklin N. Maklad G. Greenhaw I. Wilkins MD 《黑龙江环境通报》1995,15(2):179-182
The diagnosis of Freeman–Sheldon syndrome was made by ultrasonographic evaluation of a 20-week fetus with a positive family history. The ultrasonographic features were abnormalities of the extremities and mouth. 相似文献
759.
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
760.
Joe Leigh Simpson James L. Mills George G. Rhoads George C. Cunningham Howard J. Hoffman Mary R. Conley 《黑龙江环境通报》1991,11(8):641-648
No clear answer concerning whether multivitamin/folate supplementation prevents neural tube defects (NTDs) is provided by three studies in the United States. All these studies are occurrence in nature, no recurrence studies having been conducted. The Atlanta Birth Defects Study is subject to pronounced memory and recall biases, the length between event and interview being as long as 16 years. In a second study (Boston University), objections can be raised to certain aspects of the experimental design, and the claim that 22 per cent of women started vitamins sufficiently early after pregnancy diagnosis to influence NTD formation is suspicious. Our NICHD case control study of 541 women in California and Illinois revealed no evidence for multivitamins or folic acid preventing NTDs. U.S. public policy-makers face difficulties in applying results of recurrence or occurrence studies in high-risk areas to low-risk areas in the U.S. 相似文献