全文获取类型
收费全文 | 380篇 |
免费 | 19篇 |
国内免费 | 46篇 |
专业分类
安全科学 | 38篇 |
环保管理 | 33篇 |
综合类 | 225篇 |
基础理论 | 101篇 |
环境理论 | 1篇 |
污染及防治 | 16篇 |
评价与监测 | 10篇 |
社会与环境 | 9篇 |
灾害及防治 | 12篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 4篇 |
2014年 | 8篇 |
2013年 | 17篇 |
2012年 | 8篇 |
2011年 | 32篇 |
2010年 | 12篇 |
2009年 | 13篇 |
2008年 | 16篇 |
2007年 | 17篇 |
2006年 | 28篇 |
2005年 | 20篇 |
2004年 | 23篇 |
2003年 | 18篇 |
2002年 | 16篇 |
2001年 | 13篇 |
2000年 | 4篇 |
1999年 | 9篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 14篇 |
1994年 | 15篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 17篇 |
1990年 | 3篇 |
1989年 | 14篇 |
1988年 | 10篇 |
1987年 | 13篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 4篇 |
排序方式: 共有445条查询结果,搜索用时 296 毫秒
161.
Sialic acid storage disorders, Salla disease (SD) and a severe infantile form of disease (ISSD), are recessively inherited allelic lysosomal storage disorders due to impaired egress of free sialic acid from lysosomes. Fourteen pregnancies at risk of adult-type free sialic acid storage disease, SD, were monitored by sialic acid assays, genetic linkage or mutation detection analyses using chorionic villus samples. Three affected and 12 unaffected fetuses were identified. The first studies were based on the sialic acid assays alone, but the location of the gene enabled the use of genetic linkage analysis and, more recently, the identification of the SLC17A5 gene and disease-causing mutations added yet another possibility for prenatal studies. A missense mutation 115C→T (R39C) is present in 95% of all Finnish SD alleles, providing an easy and reliable means of diagnostic studies. Both molecular and biochemical (sialic acid assay) studies can be used for prenatal diagnosis of free sialic acid storage diseases. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
162.
Stefano Regis Mirella Filocamo Raffaella Mazzotti Roberto Cusano Fabio Corsolini Gloria Bonuccelli Marina Stroppiano Rosanna Gatti 《黑龙江环境通报》2001,21(8):668-671
A prenatal diagnosis of Pelizaeus-Merzbacher disease (PMD) resulting from proteolipid protein gene (PLP) duplication was performed by a quantitative fluorescent multiplex PCR method. PLP gene copy number was determined in the proband, the pregnant mother, the male fetus and two aunts. Small amounts of genomic DNA extracted from peripheral blood and from chorionic villi were used. The fetus, in common with the proband, was identified as PMD-affected being a carrier of the PLP gene duplication, inherited from the mother, while the two aunts were non-carriers. The data obtained were confirmed by segregation analysis of a PLP-associated dinucleotide-repeat polymorphism amplified by the same multiplex PCR. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
163.
Matthew R. Auer 《Sustainability Science》2007,2(2):179-187
It has been nearly 20 years since a working definition for “sustainable development” was put forward by the World Commission
on Environment and Development. The concept endures in the mission statements and frameworks of action of various societal
actors, including those of neighborhood associations, metropolitan development authorities, environmental ministries, and
United Nations (UN) specialized organizations, to name a few. Yet many observers doubt that sustainable development is occurring
in poor countries. This failure, the critics contend, stems from miserly transfers of foreign aid. The extent to which inadequate
aid is to blame for poor environmental/developmental outcomes is an open question. But vocal demands for increasing aid to
meet sustainable development goals come from many parts of society and are persistent. Exhortations for more aid to help poor
countries are noble, perhaps even justifiable, but there are understandable doubts about the wisdom of transferring large
capital and technical resources to countries that are slow to adopt needed institutional reforms. Aid without institutional
reform is a recipe for wasted resources and donor fatigue. Worse, it may enhance inequities of wealth and power in recipient
countries. There are few illustrations to draw on demonstrating how institutionally impoverished societies are affected when
they are compelled to absorb massive aid inputs over a short period––a remedy suggested by some prominent aid experts. As
a proxy, it is valuable to examine instances where swift macroeconomic changes, spurred by external investment and export-led
growth, has occurred without significant institutional development. The case of Equatorial Guinea and its sudden oil riches
is examined to discern whether, in the absence of meaningful institutional reform, rapid and profound increases in foreign
direct investment and export income enable poverty alleviation and sustainable development.
相似文献
Matthew R. AuerEmail: |
164.
165.
166.
Since the early 1960s, many investigators have reported that blackfoot disease, a peripheral vascular disease, observed in southwestern Taiwan is due to drinking the higher arsenic concentration in well water. However, recent studies indicated that the relationship with blackfoot disease is not only with arsenic but also humic substances. This paper presents some results concerning the characterization (such as fluorescence, elemental composition, molecular weight and carbon distribution) of humic substances isolated from the Fuhsing well water of the blackfoot disease area. For comparison, the dissolved organic carbon (DOC) and humic substances in the normal well water from Chiuying and the Nanwan coastal water were also analyzed. In general, in the well water of the blackfoot disease area, extremely high concentrations of DOC (18.5mg/L) and fulvic acid (7.54mg/L) with high fluorescence intensity (59.1, equivalent to 0.0282uM quinine sulfate solution) and high percentages (over 50%) of low molecular weights of less than 1,000 were obtained compared with those of normal waters. C‐13 Nuclear magnetic resonance spectroscopy showed a high content (37.2%) of aromatic carbon. These higher concentrations of DOC and fulvic acid with the higher content of aromatic carbon in well water might be one of the key factors causing the blackfoot disease in Taiwan. 相似文献
167.
大骨节病区硒元素分布的调控机理研究——以四川省阿坝地区为例 总被引:5,自引:0,他引:5
分析了阿坝地区的岩石、饮用水、农作物及其根系土中硒的不同存在形态的分布,并结合生物有效性深入研究了硒元素分布与大骨节病病因的联系和调控机理.阿坝地区的环境(岩石、土壤、水)中全硒浓度、农作物中硒的富集系数和水溶性硒占总硒的含量均远低于非病区;硒在氧化还原条件(Eh平均值143.27 mV)和酸碱度(pH 6.51—8.48)的控制下主要以亚硒酸态的稳定形式存在.元素铝、铁等的富集可能会促进硒的沉淀和络合,制约硒的生物有效利用率,进而导致人体硒摄入不足,最终激发人类微小病毒B19(HPV B19)的毒性,引发大骨节病.通过采取土壤增施硒肥、改善水质、改变膳食结构等方法可以有效地提高环境中硒的水平及其生物有效性,以缓解大骨节病的病情及发病率. 相似文献
168.
我国现行职业病诊断鉴定法律制度存在较大缺陷,使得受害劳动者维权乏力,笔者在分析探讨职业病诊断鉴定制度所存相关问题的基础上,有针对性地提出改革完善的相应建议,同时对新出台的《职业病防治法修正案(草案)》的有关修订内容做出评议。 相似文献
169.
Chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), is widespread among amphibians in northeastern North America. It is unknown, however, whether Bd has the potential to cause extensive amphibian mortalities in northeastern North America as have occurred elsewhere. In the laboratory, we exposed seven common northeastern North American amphibian species to Bd to assess the likelihood of population-level effects from the disease. We exposed larval wood frogs (Lithobates sylvaticus) and postmetamorphic frogs of six other species to two different strains of Bd, a northeastern strain (JEL404) and a strain that caused die-offs of amphibians in Panama (JEL423), under ideal in vitro growth conditions for Bd. Exposed American toads (Anaxyrus americanus) all died; thus, this species may be the most likely to die from Bd-caused disease in the wild. Both Bd strains were associated with mortalities of wood frogs, although half the metamorphs survived. The Bd strain from Panama killed metamorphic green frogs (L. clamitans), whereas the northeastern strain did not, which means novel strains of Bd may lead to death even when local strains may not. No mortality was observed in four species (bullfrogs [L. catesbeianus], northern leopard frogs [L. pipiens], spring peepers [Pseudacris crucifer], and blue-spotted salamanders [Ambystoma laterale]) and in some individuals of green frogs and wood frogs that we exposed. This finding suggests these six species may be Bd vectors. Our results show that systematic exposures of amphibian species to Bd in the laboratory may be a good first step in the identification of species susceptible to Bd-caused declines and in directing regional conservation efforts aimed at susceptible species. 相似文献
170.
Intraspecific crop diversification is thought to be a possible solution to the disease susceptibility of monocultured crops. We modelled the stratified dispersal of an airborne pathogen population in order to identify the spatial patterns of cultivar mixtures that could slow epidemic spread driven by dual dispersal mechanisms acting over both short and long distances. We developed a model to simulate the propagation of a fungal disease in a 2D field, including a reaction-diffusion model for short-distance disease dispersal, and a stochastic model for long-distance dispersal. The model was fitted to data for the spatio-temporal spread of faba bean rust (caused by Uromyces viciae-fabae) through a discontinuous field. The model was used to compare the effectiveness of eight different planting patterns of cultivar mixtures against a disease spread by short-distance and stratified dispersal. Our combined modelling approach provides a reasonably good fit with the observed data for the spread of faba bean rust. Similar predictive power could be expected for the management of resource-mediated invasions by other airborne fungi. If a disease spreads by short-distance dispersal, random mixtures can be used to slow the epidemic spread, since their spatial irregularity creates a natural barrier to the progression of a smooth epidemic wave. In the context of stratified dispersal, heterogeneous patterns should be used that include a minimum distance between susceptible units, which decreases the probability of infection by long-distance spore dispersal. We provide a simple framework for modelling the stratified dispersal of disease in a diversified crop. The model suggests that the spatial arrangement of components in cultivar mixtures has to accord with the dispersal characteristics of the pathogen in order to increase the efficiency of diversification strategies in agro-ecosystems and forestry. It can be applied in low input agriculture to manage pathogen invasion by intercropping and cultivar mixtures, and to design sustainable systems of land use. 相似文献