全文获取类型
收费全文 | 15566篇 |
免费 | 221篇 |
国内免费 | 131篇 |
专业分类
安全科学 | 474篇 |
废物处理 | 444篇 |
环保管理 | 2702篇 |
综合类 | 3542篇 |
基础理论 | 3680篇 |
环境理论 | 7篇 |
污染及防治 | 3791篇 |
评价与监测 | 722篇 |
社会与环境 | 437篇 |
灾害及防治 | 119篇 |
出版年
2018年 | 176篇 |
2017年 | 177篇 |
2016年 | 233篇 |
2015年 | 203篇 |
2014年 | 245篇 |
2013年 | 1215篇 |
2012年 | 400篇 |
2011年 | 553篇 |
2010年 | 413篇 |
2009年 | 517篇 |
2008年 | 589篇 |
2007年 | 603篇 |
2006年 | 546篇 |
2005年 | 417篇 |
2004年 | 419篇 |
2003年 | 474篇 |
2002年 | 400篇 |
2001年 | 515篇 |
2000年 | 362篇 |
1999年 | 238篇 |
1998年 | 194篇 |
1997年 | 167篇 |
1996年 | 211篇 |
1995年 | 232篇 |
1994年 | 238篇 |
1993年 | 221篇 |
1992年 | 219篇 |
1991年 | 196篇 |
1990年 | 231篇 |
1989年 | 210篇 |
1988年 | 188篇 |
1987年 | 177篇 |
1986年 | 165篇 |
1985年 | 193篇 |
1984年 | 169篇 |
1983年 | 185篇 |
1982年 | 195篇 |
1981年 | 196篇 |
1980年 | 177篇 |
1979年 | 165篇 |
1978年 | 164篇 |
1977年 | 140篇 |
1976年 | 143篇 |
1975年 | 119篇 |
1974年 | 149篇 |
1973年 | 130篇 |
1972年 | 134篇 |
1971年 | 110篇 |
1970年 | 109篇 |
1967年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
121.
Stickler syndrome is an autosomal dominant disorder of the connective tissue which includes ocular and systemic manifestations. We report on a large kindred in which we were able to demonstrate very tight linkage between the disease and the type II collagen gene (COL2A1) (LOD score 3·91 at θ=0). In a family in which the father and one of his daughters were severely affected, DNA analysis from a chorionic villus sample demonstrated that the fetus possessed the normal allele of COL2A1. Thereafter a normal child was born. 相似文献
122.
Dr. R. J. A. Wanders R. B. H. Schutgens H. van den Bosch J. M. Tager W. J. Kleijer 《黑龙江环境通报》1991,11(4):253-261
In recent years, an increasing number of inherited diseases in man have been recognized in which there is an impairment in the peroxisomal β-oxidation of very-long-chain fatty acids. In general, these disorders are associated with severe neurological and physical abnormalities and death within the first years of life. In this paper we describe our experience with regard to the prenatal diagnosis of a number of different inborn errors of peroxisomal β-oxidation. Eleven pregnancies at risk were monitored by measuring very-long-chain fatty acid levels as well as very-long-chain fatty acid β-oxidation in cultured chorionic villous fibroblasts and/or amniotic fluid cells. Five affected fetuses were identified. It is concluded that prenatal diagnosis in this group of diseases can be done reliably using cultured chorionic villous fibroblasts or amniotic fluid cells. 相似文献
123.
Five cases of mosaicism for an isochromosome of 20q have been detected from a total of 50 000 cases analysed for prenatal diagnosis by amniocentesis. Karyotypes were designated mos 46,X_/46,X_,i(20q). In all cases, the abnormal cell line was detected in more than one primary culture, thus fulfilling the criterion for true (level III) mosaicism. Indications for prenatal diagnosis were parental anxiety (two cases), low maternal serum alpha-fetoprotein (AFP) (two cases), and high maternal serum AFP (one case). Level II ultrasounds on all five fetuses were normal, and the abnormal cell line was never detected in fetal blood and/or cord blood. All five pregnancies were continued and had normal outcomes, with birth weights ranging from 2.4 to 3.8 kg. The development of all five children has been normal, with the oldest child in the study now 4 years of age. We suggest that the abnormal cell line in each case was of extrafetal origin, and that this may be one of the more common examples of this phenomenon, occurring in approximately 1/10000 prenatal diagnoses. Mosaicism i(20q) may have been missed in the past because of the higher resolution necessary to detect this subtle change. 相似文献
124.
This paper reports results of an exploratory study of prenatal diagnosis patients who experienced voluntary terminations of pregnancy following the detection of an abnormality or spontaneous miscarriages. The 121 participants were part of the national collaborative Chorionic Villus Sampling and Amniocentesis Study. They completed semi-structured telephone interviews and mailed questionnaires at 1 month and 6 months after the pregnancy losses. Scores on the Profile of Mood States showed that mood levels improved significantly over time. However, there were some declines in loss-related support from partners and others. The persisting distress and difficulties of a minority highlight the variability in women's responses to pregnancy losses. Women who lost pregnancies later in gestation, showed the greatest mood disturbances at initial assessments, used professional mental health assistance after the loss, or reported less satisfactory loss-related support from significant others showed the greatest levels of mood disturbance at the six-month assessment. Follow-up contacts with patients who lose pregnancies should be used to inform women about the variation in possible grief reactions, to assess the extent of support the women are receiving from their partners and significant others, and to provide additional follow-up or referral of those experiencing the greatest distress. 相似文献
125.
126.
The prenatal diagnosis of The Turner Syndrome is described at a menstrual age of 12 weeks. Detection of cystic hygroma was followed by vaginal chorionic villous sampling (CVS) which revealed a 45,X karyotype. Early documentation of fetal karyotype in the presence of a cystic hygroma is essential for accurate diagnosis and genetic counselling. 相似文献
127.
Plasticity of honeybee castes 总被引:1,自引:0,他引:1
128.
129.
130.