全文获取类型
收费全文 | 40175篇 |
免费 | 443篇 |
国内免费 | 548篇 |
专业分类
安全科学 | 1228篇 |
废物处理 | 1672篇 |
环保管理 | 5213篇 |
综合类 | 7637篇 |
基础理论 | 10241篇 |
环境理论 | 24篇 |
污染及防治 | 10424篇 |
评价与监测 | 2472篇 |
社会与环境 | 2016篇 |
灾害及防治 | 239篇 |
出版年
2022年 | 332篇 |
2021年 | 366篇 |
2020年 | 269篇 |
2019年 | 342篇 |
2018年 | 572篇 |
2017年 | 568篇 |
2016年 | 877篇 |
2015年 | 681篇 |
2014年 | 1024篇 |
2013年 | 3174篇 |
2012年 | 1267篇 |
2011年 | 1745篇 |
2010年 | 1374篇 |
2009年 | 1478篇 |
2008年 | 1749篇 |
2007年 | 1812篇 |
2006年 | 1571篇 |
2005年 | 1310篇 |
2004年 | 1241篇 |
2003年 | 1338篇 |
2002年 | 1190篇 |
2001年 | 1573篇 |
2000年 | 1089篇 |
1999年 | 679篇 |
1998年 | 465篇 |
1997年 | 464篇 |
1996年 | 483篇 |
1995年 | 539篇 |
1994年 | 583篇 |
1993年 | 477篇 |
1992年 | 511篇 |
1991年 | 487篇 |
1990年 | 544篇 |
1989年 | 478篇 |
1988年 | 415篇 |
1987年 | 397篇 |
1986年 | 342篇 |
1985年 | 373篇 |
1984年 | 377篇 |
1983年 | 380篇 |
1982年 | 364篇 |
1981年 | 350篇 |
1980年 | 304篇 |
1979年 | 310篇 |
1978年 | 288篇 |
1977年 | 218篇 |
1976年 | 222篇 |
1975年 | 221篇 |
1974年 | 233篇 |
1972年 | 237篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A case of spontaneous abortion after transcervical CVS is presented. Despite no evidence of bacteria in the vagina and cervix prior to sampling and the prophylactic use of Metronidazole, pathological evidence of chorioamnionitis was found. The implications of this are discussed. 相似文献
992.
993.
Reduction in serum requirement for culture of primary human amniotic fluid cells can be achieved by the addition of 10 growth-promoting factors to the nutrient medium. This supplemented medium preserves cell types normally found in amniotic fluid cell cultures supplemented with 20–30 per cent fetal bovine serum. The volume of amniotic fluid required to initiate culture can be as little as 1 ml. Amniotic fluid samples contaminated with red blood cells with no visible clot also grow well in the low serum medium. Cell-free amniotic fluid combined with equal parts of supplemented medium is useful in initiating cell culture. 相似文献
994.
995.
Prenatal diagnosis of Sandhoff disease (infantile onset) at 16 weeks gestation has been made by detection and analysis of N-acetylglucosaminyl-oligosaccharides in amniotic fluid using high performance liquid chromatography. The elution profile for the branched chain oli-gosaccharides was identical with that obtained with neonatal and infantile Sandhoff urine. The concentration of the oligosaccharides in the fluid was 1/100th that of urine but when calculated relative to creatinine the levels were similar. No oligosaccharides were detected in normal control amniotic fluids (10 patients) at a similar gestational age. Based on the levels of the amniotic fluid oligosaccharides and the sensitivity limits of the assay, prenatal diagnosis of patients with the juvenile onset form of the disease may also be possible with this technique. 相似文献
996.
997.
M. Schwartz M. Super J. Schmidtke C. Buys M. Farrall D. Halley M. Krawczak J. E. Poncin D. Loukopoulos M. Devoto 《黑龙江环境通报》1988,8(8):619-624
This paper presents data collected in Europe on 107 prenatal diagnoses of cystic fibrosis (CF) using linked DNA markers. To date, 38 children have been born without CF, as predicted, demonstrating the present rapid move from research to clinical genetic service. 相似文献
998.
Bilateral cleft lip and cleft palate can be diagnosed by ultrasonography prior to 20 weeks of pregnancy. The anomaly produces an abnormal facial profile and, on cross-section, the clefts in the maxilla are demonstrable. The method is illustrated by sonograms from a fetus in which the defect was diagnosed before trisomy 13 became known by karyotyping. 相似文献
999.
1000.