全文获取类型
收费全文 | 426篇 |
免费 | 3篇 |
国内免费 | 8篇 |
专业分类
安全科学 | 4篇 |
废物处理 | 25篇 |
环保管理 | 44篇 |
综合类 | 50篇 |
基础理论 | 107篇 |
污染及防治 | 125篇 |
评价与监测 | 60篇 |
社会与环境 | 18篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 2篇 |
2022年 | 18篇 |
2021年 | 8篇 |
2020年 | 13篇 |
2019年 | 9篇 |
2018年 | 14篇 |
2017年 | 15篇 |
2016年 | 21篇 |
2015年 | 15篇 |
2014年 | 22篇 |
2013年 | 36篇 |
2012年 | 26篇 |
2011年 | 38篇 |
2010年 | 23篇 |
2009年 | 19篇 |
2008年 | 29篇 |
2007年 | 25篇 |
2006年 | 17篇 |
2005年 | 19篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 13篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有437条查询结果,搜索用时 15 毫秒
431.
We present and discuss the results of a comprehensive study addressing the non-aerated region of the skimming flow in steep stepped spillways. Although flows in stepped spillways are usually characterized by high air
concentrations concomitant with high rates of energy dissipation, the non-aerated region becomes important in small dams and/or
spillways with high specific discharges. A relatively large physical model of such spillway was used to acquire data on flow
velocities and water levels and, then, well-resolved numerical simulations were performed with a commercial code to reproduce
those experimental conditions. The numerical runs benefited from the ability of using multi-block grids in a Cartesian coordinate
system, from capturing the free surface with the TruVOF method embedded in the code, and from the use of two turbulence models: the k-e{k{-}\varepsilon} and the RNGk-e{k{-}\varepsilon} models. Numerical results are in good agreement with the experimental data corresponding to three volumetric flow rates in
terms of the time-averaged velocities measured at diverse steps in the spillway, and they are in very satisfactory agreement
for water levels along the spillway. In addition, the numerical results provide information on the turbulence statistics of
the flow. This work also discusses important aspects of the flow, such as the values of the exponents of the power-law velocity
profiles, and the characteristics of the development of the boundary layer in the spillway. 相似文献
432.
Departing from a theoretical methodology, we estimate empirically an index of adaptive capacity (IAC) of a fishing community to the establishment of marine protected areas (MPAs). We carried out household surveys, designed to obtain information for indicators and sub-indicators, and calculated the IAC. Moreover, we performed a sensitivity analysis to check for robustness of the results. Our findings show that, despite being located between two MPAs, the fishing community of Bazán in the Colombian Pacific is highly vulnerable and that the socioeconomic dimension of the IAC constitutes the most binding dimension for building adaptive capacity. Bazán is characterized by extreme poverty, high dependence on resources, and lack of basic public infrastructure. Notwithstanding, social capital and local awareness about ecological conditions may act as enhancers of adaptive capacity. The establishment of MPAs should consider the development of strategies to confer adaptive capacity to local communities highly dependent on resource extraction. 相似文献
433.
Ana Luiza Machado Terra Roberta da Costa Kosinski Juliana Botelho Moreira Jorge Alberto Vieira Costa 《Journal of environmental science and health. Part. B》2013,48(8):709-716
The occurrence of diseases in cultivars has caused significant losses in global food production. The advancement of nanobiotechnology makes it possible to obtain new products to be used in the control of pathogens in cultivars. Silver nanoparticles can be synthesized by microalgae and are widely known for their antimicrobial activity. In addition, the biomass produced in microalgal culture for the biosynthesis of the nanoparticles also demonstrates antimicrobial properties, as it can increase the antibacterial and antifungal potential of the silver nanoparticles. In this context, this article addresses the use of microalgae to biosynthesize silver nanoparticles simultaneously with biomass production. In addition, we demonstrate the antimicrobial potential of these nanomaterials, as well as of the microalgal biomass produced in biosynthesis, to use in the control of pathogens in agriculture. 相似文献
434.
Jorge O. Ares 《Journal of the Air & Waste Management Association (1995)》2013,63(4):344-349
A strategy of research combining intense field monitoring and compartment modeling was used to characterize fluoride cycling in the semi-arid area around a newly installed aluminum factory in southern Argentina. The factory started operations In 1974 and emitted about 500 tons of gaseous fluorides to the atmosphere up to October 1976. Emphasis of research was on sedimentary or detritus cycling; periodically, samples were obtained from plant tissues, soils, sea water, and sea sediments. A compartment model of fluoride circulation at the atmosphere-vegetation interface provides further elements to Interpret the tendencies observed in field data. A fluoride budget up to October 1976 is presented showing the relative importance of environmental compartments monitored, with reference to fluoride accumulation. Plants are transient accumulators of atmospheric fluorides; soils, sea-water, and sea-sediments are sinks of the cycle. The major pathway of fluoride from terrestrial environment to coastal sea water Is along transportation with superficial soil eroded by wind. According to data here presented, it can be concluded that one wind storm can transport enough soluble fluorides to coastal waters to account for the transient differences of concentration observed. 相似文献
435.
Distribution of Heavy Metals in Surface Sediments from an Antarctic Marine Ecosystem 总被引:3,自引:0,他引:3
Andrade S Poblet A Scagliola M Vodopivez C Curtosi A Pucci A Marcovecchio J 《Environmental monitoring and assessment》2001,66(2):147-158
The concentrations of lead, cadmium, copper,chromium, iron, manganese and zinc in surfacesediments collected from Potter Cove, in the 25de Mayo Island (King George Island), Antarctica, andits drainage basin, were measured by atomic absorptionspectroscopy. The obtained results were use todetermine the areal and vertical distribution of themetals of in the Cove and potential sources of thesemetals to this environment. The geochemical datasuggest that most of the metals found in Potter Coveconstitute a redistribution of autochthonous materialswithin the ecosystem. Therefore, the metalconcentrations can be considered to be present atnatural background levels in surface sediments. 相似文献
436.
Maria Clara Pessoa Amorim José Miguel Simões Paulo Jorge Fonseca Vitor C. Almada 《Marine Biology》2010,157(3):495-503
In some marine fishes, males migrate from deeper to littoral water to breed, where they defend nests and provide parental
care. In this study, we describe seasonal patterns of shelter occupation in estuarine shallow waters and assess social aggregation
in the Lusitanian toadfish (Batrachoididae), a vocal species with male parental care. Occupation of intertidal shelters was
restricted to the breeding season but adult fish remained in subtidal regions during the non-reproductive season and they
produced sounds throughout the year. Intertidal shelters were aggregated with up to five shelters found per 2-m segment of
an 80-m transect. This aggregation probably resulted from social attraction since many segments were found unoccupied. Moreover,
shelters contained on average two fish (maximum of nine). Based on size, shelters with multiple fish seemed to contain females,
or possibly sneakers, but also more than one type I male inside, indicating a high social tolerance for conspecifics. 相似文献
437.
Carolina Briones Ricardo Gui?ez Orlando Garrido Pablo A. Oyarzún Jorge E. Toro Montse Pérez 《Marine Biology》2012,159(8):1865-1870
For the first time in a marine bivalve species, geographic intraspecific variation in sperm morphology in the Chilean mussel, Perumytilus purpuratus, is reported. Samples were obtained in December 2010 from the rocky intertidal at three locations: Antofagasta (23o44′01.08′′S, 70o26′26.11′′W), Valparaíso (32o57′23.07′′S, 71o33′01.86′′W), and Valdivia (39°50′44.26′′S, 73°25′51.99′′W). Scanning electron microscopy was used to describe sperm traits, and genetic data were obtained by sequencing a 16S mtDNA 427-bp fragment. The results showed geographic intraspecific variation with two statistically significant patterns of genetically differentiated sperm morphologies. One genetic clade was found for Antofagasta and Valparaíso, displaying a unique sperm morphotype with a short acrosome accounting for 26 % of the head length, and the other from Valdivia, with a larger acrosome occupying 47 % of the head length. These results will lead to new research to distinguish among alternative hypotheses: the presence of cryptic species, incipient speciation, or a polymorphism in sperm traits of P. purpuratus. 相似文献