全文获取类型
收费全文 | 95164篇 |
免费 | 1244篇 |
国内免费 | 1314篇 |
专业分类
安全科学 | 3849篇 |
废物处理 | 3582篇 |
环保管理 | 14454篇 |
综合类 | 21522篇 |
基础理论 | 26913篇 |
环境理论 | 73篇 |
污染及防治 | 16855篇 |
评价与监测 | 5749篇 |
社会与环境 | 4145篇 |
灾害及防治 | 580篇 |
出版年
2022年 | 847篇 |
2021年 | 851篇 |
2020年 | 684篇 |
2019年 | 898篇 |
2018年 | 1277篇 |
2017年 | 1269篇 |
2016年 | 2265篇 |
2015年 | 1866篇 |
2014年 | 2603篇 |
2013年 | 9280篇 |
2012年 | 2459篇 |
2011年 | 2887篇 |
2010年 | 3389篇 |
2009年 | 3530篇 |
2008年 | 2489篇 |
2007年 | 2383篇 |
2006年 | 2596篇 |
2005年 | 2527篇 |
2004年 | 2781篇 |
2003年 | 2686篇 |
2002年 | 2184篇 |
2001年 | 2610篇 |
2000年 | 2184篇 |
1999年 | 1594篇 |
1998年 | 1393篇 |
1997年 | 1388篇 |
1996年 | 1519篇 |
1995年 | 1601篇 |
1994年 | 1494篇 |
1993年 | 1347篇 |
1992年 | 1347篇 |
1991年 | 1303篇 |
1990年 | 1269篇 |
1989年 | 1223篇 |
1988年 | 1051篇 |
1987年 | 1001篇 |
1986年 | 994篇 |
1985年 | 1074篇 |
1984年 | 1161篇 |
1983年 | 1175篇 |
1982年 | 1174篇 |
1981年 | 1095篇 |
1980年 | 953篇 |
1979年 | 923篇 |
1978年 | 826篇 |
1977年 | 712篇 |
1976年 | 638篇 |
1975年 | 607篇 |
1973年 | 630篇 |
1972年 | 643篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
291.
M. Peter Marinkovich MD Guerrino Meneguzzi Robert E. Burgeson Claudine Blanchet-Bardon Karen A. Holbrook Lynne T. Smith Angela M. Christiano Jean-Paul Ortonne 《黑龙江环境通报》1995,15(11):1027-1034
Herlitz junctional epidermolysis bullosa (HJEB) is a severe blistering disorder which usually results in death during infancy. We have previously shown that the anchoring filament protein laminin-5 (kalinin/nicein), which mediates keratinocyte attachment and dermal–epidermal cohesion, is abnormally expressed in individuals with HJEB. Laminin-5 was detected by Western blot analysis in amniotic fluid from 44 consecutive normal secondtrimester control pregnancies, but was undetectable in second-trimester amniotic fluid from four pregnancies with fetuses affected by HJEB. In one case of severe non-Herlitz JEB, laminin-5 was detected in both amniotic fluid and skin. In human amniotic fluid, the laminin-5 a3 subunit was processed to a major 165 kD species and a minor 145 kD species and the β2 subunit was partially processed to 105 kD. Although laminin-5 was covalently associated with laminin-6 (K-laminin) in amniotic membrane, no covalent interaction was detected in amniotic fluid. Laminin-5 from amniotic fluid strongly supported keratinocyte attachment. These results suggest that Western blot analysis of second-trimester amniotic fluid is useful in determining the prenatal diagnosis of HJEB and that laminin-5 may serve a physiologically important function in amniotic fluid. 相似文献
292.
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
293.
Trisomy 10 was detected at amniocentesis undertaken following observation of fetal nuchal oedema. This is the first report of fetal trisomy 10 in association with nuchal oedema. The physical features of fetal trisomy 10 are described. 相似文献
294.
Ariel Weissman Reuwen Achiron M.D. Jacob Kuint Shlomo Lipitz Shlomo Mashiach Itamar Avigad 《黑龙江环境通报》1994,14(9):888-891
A case of gastric outlet obstruction diagnosed prenatally at 22 weeks' gestation is described. The differential diagnosis and the clinical management of this rare condition are discussed, and an updated literature review is presented. 相似文献
295.
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
296.
Dr Alan E. Donnenfeld Larry R. Glazerman Denise M. Cutillo Ronald J. Librizzi Stuart Weiner 《黑龙江环境通报》1989,9(5):301-308
Selective termination by intracardiac potassium chloride injection was performed in twins discordant for hydrocephaly at 20 weeks' gestation. Because of the potential for vascular anastomoses to exist between the twins, fetal angiography was performed prior to the selective termination procedure. Determination of vascular connections between the fetuses was hindered by fetal bradycardia following intracardiac administration of contrast material. Selective termination was performed without difficulty using intracardiac potassium chloride (KCl) to produce asystole in the twin with hydrocephaly. The unaffected fetus appeared active and had a normal heart rate during and immediately after the procedure. However, both twins were found to have died the following day. Pathologic examination documented several vascular anastomoses between the monochorionic, diamniotic fetuses. A likely cause of death was exsanguination of the normal twin into the abnormal one. This case illustrates the difficulties encountered in selective termination of monozygotic twins and, to our knowledge, represents the first reported use of intrauterine fetal angiography. 相似文献
297.
298.
Plasticity of honeybee castes 总被引:1,自引:0,他引:1
299.
Fibroblasts from a fetus with the prenatal diagnosis of mosaic trisomy 20 were cloned by dilution plating. Adenosine deaminase (ADA), a biochemical marker for chromosome 20, was assayed in trisomic clones and normal clones as control. The cytogenetic diagnosis was substantiated by demonstration of a triplex gene dosage effect for ADA in the trisomic cells. 相似文献
300.
Prenatal real-time ultrasonographic diagnosis of microphthalmia is presented. Diagnosis was made at 18 weeks' gestation in a fetus of a patient with a previous infant affected with the syndrome of cryptophthalmia with absence of septum nasi and ambiguous genitalia (Fraser syndrome). Recognition of microphthalmia as a part of Fraser syndrome and the easy visualization of fetal facial bones and orbits in the second trimester made the diagnosis possible. 相似文献