全文获取类型
收费全文 | 14925篇 |
免费 | 112篇 |
国内免费 | 96篇 |
专业分类
安全科学 | 321篇 |
废物处理 | 726篇 |
环保管理 | 1648篇 |
综合类 | 3053篇 |
基础理论 | 3306篇 |
环境理论 | 9篇 |
污染及防治 | 4209篇 |
评价与监测 | 1012篇 |
社会与环境 | 786篇 |
灾害及防治 | 63篇 |
出版年
2022年 | 207篇 |
2021年 | 206篇 |
2020年 | 98篇 |
2019年 | 113篇 |
2018年 | 285篇 |
2017年 | 231篇 |
2016年 | 412篇 |
2015年 | 270篇 |
2014年 | 451篇 |
2013年 | 1174篇 |
2012年 | 532篇 |
2011年 | 641篇 |
2010年 | 505篇 |
2009年 | 520篇 |
2008年 | 633篇 |
2007年 | 690篇 |
2006年 | 624篇 |
2005年 | 478篇 |
2004年 | 471篇 |
2003年 | 466篇 |
2002年 | 415篇 |
2001年 | 469篇 |
2000年 | 348篇 |
1999年 | 229篇 |
1998年 | 125篇 |
1997年 | 134篇 |
1996年 | 115篇 |
1995年 | 175篇 |
1994年 | 163篇 |
1993年 | 134篇 |
1992年 | 137篇 |
1991年 | 153篇 |
1990年 | 128篇 |
1989年 | 136篇 |
1988年 | 136篇 |
1987年 | 118篇 |
1986年 | 86篇 |
1985年 | 105篇 |
1984年 | 124篇 |
1983年 | 127篇 |
1982年 | 128篇 |
1981年 | 97篇 |
1980年 | 95篇 |
1979年 | 108篇 |
1978年 | 89篇 |
1977年 | 86篇 |
1976年 | 79篇 |
1975年 | 95篇 |
1974年 | 102篇 |
1965年 | 88篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
991.
Dr E. Vamos D. Pratola N. Van Regemorter M. Freund J. Flament-Durand F. Rodesch 《黑龙江环境通报》1985,5(3):209-214
Amniocentesis was performed in view of a paternal balanced chromosomal rearrangement t(4;20)(p16;p12), inv(18)(p11q11). The pregnancy was complicated by severe oligohydramnios. The fetal karyotype was unbalanced: 46XX, der(4), t(4;20)(p16;p12), inv(18) (p11q11)pat., thus resulting in partial trisomy 2Op and monosomy 4p. In addition, the amniotic fluid alpha-fetoprotein (AFP) became increasingly elevated with gestational age. The pregnancy was terminated at 25 weeks. The fetus presented with typical facial dysmorphic features, unilateral cleft lip and palate, severe renal hypoplasia, consistent with the 4p- (Wolf-Hirschhorn) syndrome. 相似文献
992.
First-trimester prenatal diagnosis of a fetus at 25 per cent risk for cystic fibrosis (CF) was performed by indirect linkage analysis of polymorphic markers using Southern blotting and polymerase chain reaction (PCR) amplification. The results revealed discrepancies in the allelic patterns between the father and the affected child, thereby complicating the prediction of fetal outcome. Analysis of a highly polymorphic VNTR locus within the human retinoblas-toma (RB) gene on chromosome 13 showed that the affected child and the fetus did not have the same biological father, and therefore the affected child could not be used to determine linkage of markers in the father of the fetus. The analysis of VNTR loci can be an effective method of resolving conflicting data during prenatal diagnosis of monogenic diseases. 相似文献
993.
994.
Michal Hejcman Michaela Klaudisová Pavla Hejcmanová Vilém Pavlů Martina Jones 《Agriculture, ecosystems & environment》2009,129(1-3):91-96
Calamagrostis villosa has recently expanded in Nardus stricta-dominated sub-alpine grassland of the Giant Mountains (Krkono?e/Karkonosze, the Czech Republic). To investigate whether this expansion has been promoted by high nitrogen deposition or by the cessation of agricultural management, grassland plots dominated by C. villosa were manipulated with four treatments: control (Con), fertilised (Fer), cut (Cut) and cut–fertilised (Cut–Fer). NH4NO3 was used at the rate of 30 kg N ha?1 and fertilisation and cutting were performed once a year after data collection in late July between 2000 and 2006.Plant species composition (analysed by RDA) was significantly influenced by cutting but not by fertilisation. Cutting reduced the cover, biomass, sward height and tiller density of C. villosa. Seedlings of N. stricta and panicles of C. villosa were recorded only in plots with cutting management.To investigate the effect of treatments on the spread of C. villosa, grassland sods dominated by N. stricta were transplanted into the experimental plots. Six years later, the density and cover of C. villosa spreading into the N. stricta sods were highest in Fer treatment.C. villosa was recognised as a defoliation-sensitive species and this sensitivity cannot be overcome by an increase in N supply. Recent expansion of C. villosa in the sub-alpine grassland can by explained by a long-term succession after the cessation of agricultural management and an increase in the N availability in recent decades. 相似文献
995.
We report a case of intrapericardial teratoma following in utero demise at 29 weeks with nonimmune hydrops. The diagnosis was strongly suggested by ultrasound findings and confirmed by fetopathology. The mechanism whereby intrapericardial teratomas may lead to hydrops and death is massive pericardial effusion responsible for compressive tamponade. When prenatal diagnosis is performed before this stage, in utero interventions can obtain decompression, and the birth can be planned with rapid and appropriate management of the neonate. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
996.
Maria Okumura Vera Aparecida dos Santos Mário E. Camargo Regina Schultz Marcelo Zugaib 《黑龙江环境通报》2004,24(3):179-181
The prenatal diagnosis of congenital transmission of Chagas' disease in a pregnant woman with the indeterminate form of the disease is reported. Sonography revealed fetal hydrops at 31 weeks' gestation. Anti-Trypanosoma cruzi IgM and IgG antibodies were negative in the fetal blood sampled by cordocentesis, but T. cruzi trypomastigotes were found in its buffy coat. Owing to anemia, in utero exchange transfusion was undertaken, but fetal demise ensued. Labor was induced and a stillborn infant weighing 2030 g was delivered. The pathological examination revealed placentitis and meningoencephalitis, myocarditis and splenitis in the stillborn fetus. Amastigotes were found in the myocardium, brain and placenta. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
997.
Officially the environmental protection from industrial insults began with Rachel Carson''''s book "The Silent Spring" in .Protection priorities have since changed.They can be grouped into three successive phases.…… 《中国人口.资源与环境(英文版)》2007,5(3):9-15
Officially, the environmental protection from industrial insults began with Rachel Carson's book "The Silent Spring" in 1963. Protection priorities have since changed. They can be grouped into three successive phases. 相似文献
998.
Combining a computational fluid dynamics (CFD) model and a multi-zonal model, a study was carried out on radon entry through the complex substructure of a house with a cellar. The uniqueness of the radon entry problem in this type of house was due to the involvement of two radon entry routes to two chambers: the cellar and the living area of the house. Soil gas carrying radon was driven through the two routes by two coupled disturbance pressures in the chambers. The effects of temperature differences were considered as another driving force for the radon entry. Examined in this study were the effects of the geometry of the substructure, air permeability of the soil, air-tightness of the cellar shell, and cellar ventilation on radon entry to both the cellar and the living area. The ground floor covering on top of the soil outside a cellar wall increased radon entry through this wall by about 68%, as radon built up to a very high level under the covering. The effect of cellar ventilation was found as follows: the cellar ventilation created a layer of airflow in the soil under the ground floor; the flow passed over a crack in the ground floor, the entry route to the living area, diluting the radon in the area. Hence, the soil gas entering the living area carried less radon. Cellar ventilation seems more effective in reducing radon entry to the living area in a more permeable soil and leaky cellar shell; a moderate cellar ventilation condition achieved 77% reduction in radon entry to the area. When permeability of these two materials was lower and soil radon content remained the same, the chances of radon entry was also lower; hence, the indoor radon level was lower and no radon control was needed. When such soil contains high radon concentration, other mitigation measures must be sought. 相似文献
999.
1000.
The present study focuses on the use of solid waste generated by the steel works in Brazil for manufacturing clay-based structural products. The waste sample was characterized regarding chemical composition, X-ray diffraction, particle size, morphology, specific surface and plastic properties. The waste was added in gradual proportions to a kaolinitic clay from zero up to 3 wt.%. Ceramic bodies were formed by vacuum extrusion and fired at 950 degrees C. The physical-mechanical properties (linear shrinkage, water absorption, apparent density and flexural strength) of the resulting clay/solid waste mixtures were determined. In addition, leaching tests were performed according Brazilian Standards as well as a preliminary analysis of gases evolved during the thermal process. It was found that the solid waste is formed by irregular particles, ranging in size from 1 to 500 microm. The test results indicate that solid wastes generated by steel works can be used as filler in construction materials, thereby increasing reuse in an environmentally safe manner. 相似文献