全文获取类型
收费全文 | 2722篇 |
免费 | 17篇 |
国内免费 | 33篇 |
专业分类
安全科学 | 76篇 |
废物处理 | 143篇 |
环保管理 | 266篇 |
综合类 | 485篇 |
基础理论 | 552篇 |
环境理论 | 2篇 |
污染及防治 | 797篇 |
评价与监测 | 246篇 |
社会与环境 | 185篇 |
灾害及防治 | 20篇 |
出版年
2023年 | 27篇 |
2022年 | 87篇 |
2021年 | 103篇 |
2020年 | 53篇 |
2019年 | 41篇 |
2018年 | 99篇 |
2017年 | 101篇 |
2016年 | 123篇 |
2015年 | 73篇 |
2014年 | 117篇 |
2013年 | 171篇 |
2012年 | 129篇 |
2011年 | 162篇 |
2010年 | 118篇 |
2009年 | 105篇 |
2008年 | 121篇 |
2007年 | 113篇 |
2006年 | 77篇 |
2005年 | 118篇 |
2004年 | 156篇 |
2003年 | 152篇 |
2002年 | 96篇 |
2001年 | 75篇 |
2000年 | 33篇 |
1999年 | 33篇 |
1998年 | 14篇 |
1997年 | 26篇 |
1996年 | 16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 | 11篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1979年 | 8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2772条查询结果,搜索用时 187 毫秒
981.
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
982.
Dadvand P Basagaña X Figueras F Amoly E Tobias A de Nazelle A Querol X Sunyer J Nieuwenhuijsen MJ 《Journal of environmental monitoring : JEM》2011,13(11):3222-3228
Desert dust is one of the natural contributors to atmospheric particulate matter worldwide. Although particulate pollution has been shown to adversely affect pregnancy, the available evidence on the impact of dust episodes on pregnancy is very scarce. The aim of this study was to evaluate the impact of Saharan dust episodes on pregnancy complications (preeclampsia and bacteriuria) and outcomes (birth weight and gestational age at delivery). This study was based on a cohort of births (N = 3565) that occurred in a major university hospital in Barcelona during 2003-2005. To determine Saharan dust episodes, we developed a two-stage approach based on meteorological evidence of the presence of Saharan dust cloud over the region and unusually high levels of particulate levels on the ground while taking account of traffic sources. The associations between the number of Saharan dust episodes during whole pregnancy as well as each pregnancy trimester and pregnancy complications and outcomes were analysed. There were 152 days (out of 838 days) with Saharan dust cloud over the region from which 45 days were determined as episodic days. We did not observe any statistically significant harmful effect of Saharan dust episodes on our included pregnancy complications and outcomes. However, we observed a small but statistically significant increase in gestational age at delivery in association with the number of episodic days during the third trimester and whole pregnancy (0.8 and 0.5 days respectively). Our findings were not suggestive for any adverse effect of Saharan dust episodes on our included pregnancy complications and outcomes. 相似文献
983.
Pourcelot L Boulet B Le Corre C de Vismes Ott A Cagnat X Loyen J Fayolle C Van Hecke W Martinez B Petit J Kaltenmeier R Gieré R 《Journal of environmental monitoring : JEM》2011,13(5):1327-1336
Cypress needles collected at the edge of the Malvési uranium facility (SW France) exhibit enhanced activities of actinides and some decay products (uranium, americium, plutonium, (230)Th, (226)Ra) compared to a remote site. These enhanced activities resulted from the release of U via smokestacks and passive release from former artificial ponds located inside the nuclear site. Enhanced activities are also observed in selected produce (wheat, lettuce, fruits) sampled from the edge of the site. However, excess actinides measured in wheat grains in 2007 are inconsistent with the activities and the uranium ratio measured in the soils. This result suggests that the studied annual crops were contaminated mainly through the short-term release of airborne actinides, and that other transfer pathways, such as, uptake through the roots or adhesion of soil particles, were negligible. 相似文献
984.
How the properties of ecosystems relate to spatial scale is a prominent topic in current ecosystem research. Despite this, spatially explicit models typically include only a limited range of spatial scales, mostly because of computing limitations. Here, we describe the use of graphics processors to efficiently solve spatially explicit ecological models at large spatial scale using the CUDA language extension. We explain this technique by implementing three classical models of spatial self-organization in ecology: a spiral-wave forming predator-prey model, a model of pattern formation in arid vegetation, and a model of disturbance in mussel beds on rocky shores. Using these models, we show that the solutions of models on large spatial grids can be obtained on graphics processors with up to two orders of magnitude reduction in simulation time relative to normal pc processors. This allows for efficient simulation of very large spatial grids, which is crucial for, for instance, the study of the effect of spatial heterogeneity on the formation of self-organized spatial patterns, thereby facilitating the comparison between theoretical results and empirical data. Finally, we show that large-scale spatial simulations are preferable over repetitions at smaller spatial scales in identifying the presence of scaling relations in spatially self-organized ecosystems. Hence, the study of scaling laws in ecology may benefit significantly from implementation of ecological models on graphics processors. 相似文献
985.
Robin?F.?A.?MoritzEmail author H.?Michael?G.?Lattorff Kendall?L.?Crous Randall?H.?Hepburn 《Behavioral ecology and sociobiology》2011,65(4):735-740
Workers of a queenless honeybee colony can requeen the colony by raising a new queen from a young worker brood laid by the
old queen. If this process fails, the colony becomes hopelessly queenless and workers activate their ovaries to lay eggs themselves.
Laying Cape honeybee workers (Apis mellifera capensis) produce female offspring as an additional pathway for requeening. We tested the frequency of successful requeening in ten
hopelessly queenless colonies. DNA genotyping revealed that only 8% of all queens reared in hopelessly queenless colonies
were the offspring of native laying worker offspring. The vast majority of queens resulted from parasitic takeovers by foreign
queens (27%) and invading parasitic workers (19%). This shows that hopelessly queenless colonies typically die due to parasitic
takeovers and that the parasitic laying workers are an important life history strategy more frequently used than in providing
a native queen to rescue the colony. Parasitism by foreign queens, which might enter colonies alone or accompanied by only
a small worker force is much more frequent than previously considered and constitutes an additional life history strategy
in Cape honeybees. 相似文献
986.
Rafael Vicente de P��dua Ferreira Solange Kazumi Sakata Vera L��cia Keiko Isiki Hissae Miyamoto Maria Helena Bellini Luis Filipe C. P. de Lima J��lio Takehiro Marumo 《Environmental Chemistry Letters》2011,9(2):209-216
The present study investigated the influence of 241Am on microbial growth and the degradation of organic waste. Leachate samples collected in a lysimeter were periodically analyzed
for bacterial growth, under both aerobic and anaerobic conditions. 241Am inhibited bacterial growth, and the degradation of organic matter was delayed in comparison with the control. Minimal inhibitory
concentration assays and survival curves revealed that it inhibits the growth of Pseudomonas putida F1. The assay also revealed that 241Am is more toxic than 238U, Zn2+ and Cd2+. This study further led to the finding of four new radionuclide-tolerant bacterial strains: Flavobacterium spp., Pseudomonas gladioli, Chryseobacterium indologenes and Ochrobactrum anthropi. The survival curves of P. gladioli, C. indologenes revealed that these bacteria are resistant to metal as consortia. 相似文献
987.
da Silveira RP Rodrigues AP Santelli RE Cordeiro RC Bidone ED 《Environmental monitoring and assessment》2011,181(1-4):165-173
This study addressed the identification and monitoring of pollution sources of terrestrial origin in rivers (domestic sewage and industrial effluents) and critical fluvial segments in highly polluted environments under tidal influence (mixing marine and continental sources) from Guanabara Bay Basin, Rio de Janeiro, Brazil. The mass balance of contaminants was determined in conditions of continuous flow (low tide) during dry season (lower dilution capability). The results allowed the evaluation of the potential of contaminant mass generation by the different river segments and the estimation of their natural and anthropogenic components. The water quality of Igua?ú and Sarapuí Rivers were evaluated for metals and biochemical oxygen demand. The method gave an excellent response, including the possibility of sources identification and contaminated river segments ranking. The approach also offers fast execution and data interpretation, being highly efficient. 相似文献
988.
Nogueira L Rodrigues AC Trídico CP Fossa CE de Almeida EA 《Environmental monitoring and assessment》2011,180(1-4):243-255
Considering that diesel oil is one of the most common aquatic contaminants, we compare the oxidative stress between two species of fish with different habitats (Pterygoplichthys anisitsi, benthic and Oreochromis niloticus, nektonic) exposed to diesel oil. Malondialdehyde concentrations (MDA) and the activities of ethoxyresorufin-O-deethylase (EROD), glutathione S-transferase (GST), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase were all analyzed in the fishes' livers and gills after 2 and 7 days of exposure to different concentrations of diesel (0.1 and 0.5 mL/L). In the tilapia, MDA levels and the activities of EROD and GST activity in the liver, as well as MDA levels and the activities of GST and SOD in the gill had statistically significant differences between the treatments and between the times of exposure. For the catfish, the same occurred in the case of MDA, EROD, and SOD in the liver and in CAT and SOD in the gills. There were significant differences in the enzyme activity and lipid peroxidation between the species. Although the activity of most enzymes seemed to be more expressive and responsive to diesel in O. niloticus, diesel oil also caused significant effects on oxidative stress parameters in P. anisitsi, even though this species is benthic and thus has less access to insoluble fractions of diesel oil. Therefore, both species can be used as sentinel organisms in environmental biomonitoring of diesel contamination. 相似文献
989.
Cristiane Rossi de Oliveira Luiz Augusto dos Santos Madureira 《Environmental monitoring and assessment》2011,173(1-4):91-105
Nonaromatic hydrocarbons and geochemical parameters from 17 sediment?Cwater interface samples were used to assess sources of organic matter in three harbors, located in Santa Catarina State, southern Brazil. The evaluation was based on the molar C/N/P ratios, abundance of resolved nonaromatic hydrocarbons (3.0?C25.9 ??g g???1), unresolved complex mixture, and two indexes: the carbon preference index (CPI) and the low molecular weight to high molecular weight ratio. The results indicate that the organic matter is predominantly of terrestrial origin (C/N > 10 and CPI > 2). Variations in the total organic carbon from 0.43 to 2.98 mmol g???1 and total phosphorus from 82.4 to 464.3 ??g g???1 showed no clear correlation with the silt and clay fractions of the sediments possibly due to anthropogenic input. In contrast to the low level of contamination based on the acyclic hydrocarbon distribution, the results obtained from a series of geologically stable hopanes and steranes reveal the presence of less degradable petroleum derivatives. 相似文献
990.
Peter Bröde Kalev Kuklane Victor Candas Emiel A. Den Hartog Barbara Griefahn Ingvar Holmér 《International journal of occupational safety and ergonomics》2013,19(2):231-244
The heat transferred through protective clothing under long wave radiation compared to a reference condition without radiant stress was determined in thermal manikin experiments. The influence of clothing insulation and reflectivity, and the interaction with wind and wet underclothing were considered. Garments with different outer materials and colours and additionally an aluminised reflective suit were combined with different number and types of dry and pre-wetted underwear layers. Under radiant stress, whole body heat loss decreased, i.e., heat gain occurred compared to the reference. This heat gain increased with radiation intensity, and decreased with air velocity and clothing insulation. Except for the reflective outer layer that showed only minimal heat gain over the whole range of radiation intensities, the influence of the outer garments’ material and colour was small with dry clothing. Wetting the underclothing for simulating sweat accumulation, however, caused differing effects with higher heat gain in less permeable garments. 相似文献