全文获取类型
收费全文 | 2876篇 |
免费 | 31篇 |
国内免费 | 66篇 |
专业分类
安全科学 | 103篇 |
废物处理 | 146篇 |
环保管理 | 286篇 |
综合类 | 573篇 |
基础理论 | 571篇 |
环境理论 | 2篇 |
污染及防治 | 812篇 |
评价与监测 | 263篇 |
社会与环境 | 194篇 |
灾害及防治 | 23篇 |
出版年
2023年 | 31篇 |
2022年 | 97篇 |
2021年 | 123篇 |
2020年 | 65篇 |
2019年 | 50篇 |
2018年 | 108篇 |
2017年 | 112篇 |
2016年 | 135篇 |
2015年 | 80篇 |
2014年 | 133篇 |
2013年 | 176篇 |
2012年 | 140篇 |
2011年 | 175篇 |
2010年 | 126篇 |
2009年 | 116篇 |
2008年 | 128篇 |
2007年 | 119篇 |
2006年 | 87篇 |
2005年 | 122篇 |
2004年 | 161篇 |
2003年 | 151篇 |
2002年 | 102篇 |
2001年 | 77篇 |
2000年 | 35篇 |
1999年 | 34篇 |
1998年 | 14篇 |
1997年 | 27篇 |
1996年 | 17篇 |
1995年 | 22篇 |
1994年 | 17篇 |
1993年 | 8篇 |
1992年 | 11篇 |
1991年 | 16篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 5篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 11篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1979年 | 9篇 |
1977年 | 3篇 |
1975年 | 3篇 |
1970年 | 3篇 |
1966年 | 3篇 |
1964年 | 4篇 |
1961年 | 3篇 |
排序方式: 共有2973条查询结果,搜索用时 46 毫秒
961.
Estienney Marie Daval-Frerot Philippe Aho-Glélé Ludwig-Serge Piroth Lionel Stabile Pascal Gerbet Jean-Yves Rouleau Romain de Rougemont Alexis Belliot Gaël 《Food and environmental virology》2022,14(2):217-221
Food and Environmental Virology - Disinfection of hospital facilities and ambulances is an important issue for breaking the chain of transmission of viral pathogens. Hydrogen peroxide has provided... 相似文献
962.
In agricultural landscapes, studies that identify factors driving species richness and occupancy are important because they can guide farmers to use conservation practices that minimize species loss. In this context, anurans are threatened by habitat loss because they depend on the characteristics of both local water bodies and adjacent landscapes. We used a model selection approach to evaluate the influence of local and landscape variables in determining anuran species richness and occurrence in 40 freshwater bodies in a heavily deforested region of semideciduous Atlantic Forest in southeastern Brazil. Our aim was to develop recommendations for conservation of anuran communities in rural areas. Pond hydroperiod and area were the most important variables for explaining anuran species richness and occupancy, with greatest species richness being found in water bodies with intermediate hydroperiod and area. Other important variables that reflected individual species occupancies were the number of vegetation types and pond isolation. In addition, recent studies evidenced that water bodies near forest fragments have higher anuran abundance or diversity. In conclusion, we suggest the maintenance of semi-permanent ponds, isolated from large rivers or reservoirs and near forest fragments, as an effective strategy to conserve anuran fauna in agricultural landscapes of southeastern Brazil. Brazilian government requires the maintenance of forests as legal reserve in each farm, and farmers need to maintain ponds as drinking water for cattle or crop irrigation. For this reason, the guidelines suggested in the present study can be easily adopted, without additional costs to rural productivity. 相似文献
963.
采用实时荧光定量PCR和Illumina高通量测序技术对秋季辽河口芦苇湿地水体中一昼夜细菌和古菌群落特征进行了研究.测序共获得52802条细菌和106091条古菌高质量序列,以97%的相似性聚类并抽平后共划分了530和979个OTU.结果表明,湿地水体中浮游细菌和古菌群落丰度均在早上达到最高值,夜晚达到最低值.细菌和古菌群落多样性指数均存在周期日变化,不同时间细菌和古菌群落结构和组成具有显著差异.此外,古菌群落组成特征表明辽河口芦苇湿地具有较高的潜在甲烷生成能力.本研究为进一步认识河口湿地细菌和古菌群落特征和功能奠定了基础. 相似文献
964.
Rodolpho?S.?T.?MenezesEmail author Vanessa?B.?Bardella Diogo?C.?Cabral-de-Mello Daercio?A.?A.?Lucena Eduardo?A.?B.?Almeida 《Die Naturwissenschaften》2017,104(9-10):85
Despite the (TTAGG)n telomeric repeat supposed being the ancestral DNA motif of telomeres in insects, it was repeatedly lost within some insect orders. Notably, parasitoid hymenopterans and the social wasp Metapolybia decorata (Gribodo) lack the (TTAGG)n sequence, but in other representatives of Hymenoptera, this motif was noticed, such as different ant species and the honeybee. These findings raise the question of whether the insect telomeric repeat is or not phylogenetically predominant in Hymenoptera. Thus, we evaluated the occurrence of both the (TTAGG)n sequence and the vertebrate telomere sequence (TTAGGG)n using dot-blotting hybridization in 25 aculeate species of Hymenoptera. Our results revealed the absence of (TTAGG)n sequence in all tested species, elevating the number of hymenopteran families lacking this telomeric sequence to 13 out of the 15 tested families so far. The (TTAGGG)n was not observed in any tested species. Based on our data and compiled information, we suggest that the (TTAGG)n sequence was putatively lost in the ancestor of Apocrita with at least two subsequent independent regains (in Formicidae and Apidae). 相似文献
965.
María M. Martorell Hipólito F. Pajot Pablo M. Ahme Lucía I.C. de Figueroa 《环境科学学报(英文版)》2017,29(3):78-87
Azo dyes are extensively used in textile dyeing and other industries. Effluents of dying industries are specially colored and could cause severe damage to the environment. The anaerobic treatment of textile dying effluents is nowadays the preferred option, but it could generate carcinogenic aromatic amines. Recently, yeasts have become a promising alternative, combining unicellular growth with oxidative mechanisms. This work reports the characterization of the first methylotrophic yeast with dye decolorizing ability, Candida boidinii MM 4035 and some insights into its decoloration mechanism. The analysis of two selected media revealed a possible two stages mechanism of Reactive Black 5 decoloration. In glucose poor media, decoloration is incomplete and only the first stage proceeds, leading to the accumulation of a purple compound. In media with higher glucose concentrations, the yeast is able to decolorize totally an initial concentration of 200 mg/L. The entire process is co-metabolic, being largely dependent on glucose concentration but being able to proceed with several nitrogen sources. Manganese dependent peroxidase but not laccase activity could be detected during decoloration. Aromatic amines do not accumulate in culture media, supporting an oxidative decoloration mechanism of unknown ecophysiological relevance. 相似文献
966.
Johannes G. Leskens Christian Kehl Tim Tutenel Timothy Kol Gerwin de Haan Guus Stelling Elmar Eisemann 《Mitigation and Adaptation Strategies for Global Change》2017,22(2):307-324
Developing strategies to mitigate or to adapt to the threats of floods is an important topic in the context of climate changes. Many of the world’s cities are endangered due to rising ocean levels and changing precipitation patterns. It is therefore crucial to develop analytical tools that allow us to evaluate the threats of floods and to investigate the influence of mitigation and adaptation measures, such as stronger dikes, adaptive spatial planning, and flood disaster plans. Up until the present, analytical tools have only been accessible to domain experts, as the involved simulation processes are complex and rely on computational and data-intensive models. Outputs of these analytical tools are presented to practitioners (i.e., policy analysts and political decision-makers) on maps or in graphical user interfaces. In practice, this output is only used in limited measure because practitioners often have different information requirements or do not trust the direct outcome. Nonetheless, literature indicates that a closer collaboration between domain experts and practitioners can ensure that the information requirements of practitioners are better aligned with the opportunities and limitations of analytical tools. The objective of our work is to present a step forward in the effort to make analytical tools in flood management accessible for practitioners to support this collaboration between domain experts and practitioners. Our system allows the user to interactively control the simulation process (addition of water sources or influence of rainfall), while a realistic visualization allows the user to mentally map the results onto the real world. We have developed several novel algorithms to present and interact with flood data. We explain the technologies, discuss their necessity alongside test cases, and introduce a user study to analyze the reactions of practitioners to our system. We conclude that, despite the complexity of flood simulation models and the size of the involved data sets, our system is accessible for practitioners of flood management so that they can carry out flood simulations together with domain experts in interactive work sessions. Therefore, this work has the potential to significantly change the decision-making process and may become an important asset in choosing sustainable flood mitigations and adaptation strategies. 相似文献
967.
Aim
Injuries in adolescence are an important public health problem and a major cause of morbidity and mortality in this age group. This study aimed to determine the behaviour profile associated to risk of injury and the differences between genders, region and ethnic origin.Methods
A cross-sectional study design of a nationally representative sample of 1581 adolescents of the Portuguese Health Behaviour in School-Aged Children study.Results
An occurrence of one injury-related event in the previous year was reported by 21.4% of the respondents and 5.9% referred having more than one injury-related event. Boys reported higher frequency of those events when compared to girls, and non-Portuguese subjects referred higher frequency of events. Scoring higher in violence-related behaviour and psychosomatic complaints was associated to higher chances of referring more than one injury-related event.Conclusion
Gender, social background and behaviour profile are factors that seem to influence the risk of injuries. This information should guide those involved in the planning of injuries prevention programs in youth. 相似文献968.
Introduction
This study describes a method for reducing the number of variables frequently considered in modeling the severity of traffic accidents. The method's efficiency is assessed by constructing Bayesian networks (BN).Method
It is based on a two stage selection process. Several variable selection algorithms, commonly used in data mining, are applied in order to select subsets of variables. BNs are built using the selected subsets and their performance is compared with the original BN (with all the variables) using five indicators. The BNs that improve the indicators’ values are further analyzed for identifying the most significant variables (accident type, age, atmospheric factors, gender, lighting, number of injured, and occupant involved). A new BN is built using these variables, where the results of the indicators indicate, in most of the cases, a statistically significant improvement with respect to the original BN.Conclusions
It is possible to reduce the number of variables used to model traffic accidents injury severity through BNs without reducing the performance of the model.Impact on Industry
The study provides the safety analysts a methodology that could be used to minimize the number of variables used in order to determine efficiently the injury severity of traffic accidents without reducing the performance of the model. 相似文献969.
970.
Matías Feijoo Enrique P. Lessa Rocío Loizaga de Castro Enrique A. Crespo 《Marine Biology》2011,158(8):1857-1867
Several major breeding areas have been defined for the South American sea lion (Otaria flavescens) along the Atlantic Ocean including the Uruguayan and Patagonian coasts. Together with a documented and severe reduction
in population sizes caused by commercial hunting in the last century, these areas show opposite population trends. While Patagonian
populations are recovering since hunting ceased, Uruguayan populations are declining. In this context, population genetic
structure and genetic diversity were studied for the first time with both nuclear (microsatellites) and mitochondrial (control
region) markers together. Alternative scenarios were found for both markers. While mitochondrial marker showed geographically
structured populations, the nuclear loci showed a lack of geographical structure. These opposite patterns in genetic structure
could be explained by female phylopatry and high male dispersion. The reduction in population size caused by commercial hunting
did not leave a detectable footprint of bottleneck at the genetic level. 相似文献