全文获取类型
收费全文 | 1935篇 |
免费 | 16篇 |
国内免费 | 15篇 |
专业分类
安全科学 | 38篇 |
废物处理 | 95篇 |
环保管理 | 156篇 |
综合类 | 263篇 |
基础理论 | 472篇 |
环境理论 | 1篇 |
污染及防治 | 641篇 |
评价与监测 | 156篇 |
社会与环境 | 140篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 19篇 |
2022年 | 67篇 |
2021年 | 66篇 |
2020年 | 31篇 |
2019年 | 32篇 |
2018年 | 123篇 |
2017年 | 101篇 |
2016年 | 127篇 |
2015年 | 62篇 |
2014年 | 103篇 |
2013年 | 141篇 |
2012年 | 123篇 |
2011年 | 152篇 |
2010年 | 86篇 |
2009年 | 80篇 |
2008年 | 113篇 |
2007年 | 110篇 |
2006年 | 85篇 |
2005年 | 66篇 |
2004年 | 63篇 |
2003年 | 33篇 |
2002年 | 29篇 |
2001年 | 25篇 |
2000年 | 13篇 |
1999年 | 13篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 9篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 6篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1966年 | 3篇 |
1965年 | 2篇 |
1964年 | 5篇 |
1961年 | 2篇 |
1960年 | 2篇 |
1959年 | 3篇 |
1955年 | 1篇 |
1954年 | 2篇 |
排序方式: 共有1966条查询结果,搜索用时 15 毫秒
971.
Plastic pollution in freshwater ecosystems: macro-, meso-, and microplastic debris in a floodplain lake 总被引:1,自引:0,他引:1
Martin C. M. Blettler Maria Alicia Ulla Ana Pia Rabuffetti Nicolás Garello 《Environmental monitoring and assessment》2017,189(11):581
Plastic pollution is considered an important environmental problem by the United Nations Environment Programme, and it is identified, alongside climate change, as an emerging issue that might affect biological diversity and human health. However, despite research efforts investigating plastics in oceans, relatively little studies have focused on freshwater systems. The aim of this study was to estimate the spatial distribution, types, and characteristics of macro-, meso-, and microplastic fragments in shoreline sediments of a freshwater lake. Food wrappers (mainly polypropylene and polystyrene), bags (high- and low-density polyethylene), bottles (polyethylene terephthalate), and disposable Styrofoam food containers (expanded polystyrene) were the dominant macroplastics recorded in this study. Contrary to other studies, herein macroplastic item surveys would not serve as surrogates for microplastic items. This is disadvantageous since macroplastic surveys are relatively easier to conduct. Otherwise, an average of 25 mesoplastics (mainly expanded polystyrene) and 704 microplastic particles (diverse resins) were recorded per square meter in sandy sediments. Comparisons with other studies from freshwater and marine beaches indicated similar relevance of plastic contamination, demonstrating for the first time that plastic pollution is a serious problem in the Paraná floodplain lakes. This study is also valuable from a social/educational point of view, since plastic waste has been ignored in the Paraná catchment as a pollutant problem, and therefore, the outcome of the current study is a relevant contribution for decision makers. 相似文献
972.
René E. van Dijk Lidia A. Mészáros Marco van der Velde Tamás Székely Ákos Pogány János Szabad Jan Komdeur 《Behavioral ecology and sociobiology》2010,64(9):1425-1435
Engagement in extra-pair copulations is an example of the abundant conflicting interests between males and females over reproduction.
Potential benefits for females and the risk of cuckoldry for males are expected to have important implications on the evolution
of parental care. However, whether parents adjust parental care in response to parentage remains unclear. In Eurasian penduline
tits Remiz pendulinus, which are small polygamous songbirds, parental care is carried out either by the male or by the female. In addition, one
third of clutches is deserted by both male and female. Desertion takes place during the egg-laying phase. Using genotypes
of nine microsatellite loci of 443 offspring and 211 adults, we test whether extra-pair paternity predicts parental care.
We expect males to be more likely to desert cuckolded broods, whereas we expect females, if they obtain benefits from having
multiple sires, to be more likely to care for broods with multiple paternity. Our results suggest that parental care is not
adjusted to parentage on an ecological timescale. Furthermore, we found that male attractiveness does not predict cuckoldry,
and we found no evidence for indirect benefits for females (i.e., increased growth rates or heterozygosity of extra-pair offspring).
We argue that male Eurasian penduline tits may not be able to assess the risk of cuckoldry; thus, a direct association with
parental care is unlikely to evolve. However, timing of desertion (i.e., when to desert during the egg-laying phase) may be
influenced by the risk of cuckoldry. Future work applying extensive gene sequencing and quantitative genetics is likely to
further our understanding of how selection may influence the association between parentage and parental care. 相似文献
973.
Mireia Andrés Alicia Estévez Francisco Hontoria Guiomar Rotllant 《Marine Biology》2010,157(10):2329-2340
Changes in lipid class, fatty acid, fat-soluble vitamins, amino acid and minerals were studied during larval development of
Maja brachydactyla Balss, 1922 in order to provide information of its ontogeny and evaluate possible dietary deficiencies and constraints. Four
different batches were analyzed from hatching to metamorphosis using enriched Artemia as food. Cultured larvae were in a good nutritional condition as confirmed by the continuous lipid accumulation throughout
ontogeny. A regulation of polyunsaturated fatty acids (PUFA) occurred during development in order to maintain adequate basal
levels of ω-3 fatty acids (likely through a retro conversion of C20 and C22 into C18 PUFA). Variations in the tocopherol levels indicated its possible role in PUFA protection against oxidation. Essential amino
acid balance during development was not correlated with the Artemia feeding regime, but rather reflected inherent variations of the own species ontogeny. Larval requirements in essential minerals
were fully supplied by the enriched Artemia. 相似文献
974.
Andrés García María Luisa Sámano José A. Juanes Raúl Medina José A. Revilla César Álvarez 《Ecological modelling》2010,221(10):1413-263
In the last years several episodes of algae appearance affecting bathing areas have been observed in San Lorenzo Bay (north of Spain). The analysis of the collected algae revealed that they might come from near intertidal or shallow subtidal zones due to eutrophication processes or through drift algae movement by the action of marine currents. In the vicinity of this area, the expansion of the Port of Gijón (now under construction) supposes a significant modification of the coastal geometry. The magnitude of such an expansion could cause changes in the patterns of currents in the bay, with the consequent alteration of the observed algal appearance phenomena. A mathematical modelling study to evaluate the risk of generation of eutrophication processes in the San Lorenzo Bay area and the transport of drift algae from near sea bed areas was developed. This study required the use of different hydrodynamic models in order to characterize the currents caused by tides, winds and waves. The eutrophication processes in the bay were analyzed with a depth-averaged two-dimensional eutrophication model which deals with eight water quality variables. Calibration of model parameters with the observed data from a field survey was performed. A reasonable agreement with the field measurements was achieved. Model results showed that the maximum phytoplankton concentrations were below eutrophic conditions. Although, the port expansion has led to an increment of phytoplankton concentrations, chlorophyll a levels were not representative of eutrophic conditions. To analyse the transport of drift algae, a methodology based on the utilization of a two-dimensional model which solves the depth-averaged advection-diffusion equation considering seaweed as a conservative tracer was developed and applied. Numerical modelling allowed the identification of the coastal areas that seems to be the source of the seaweed found on the beach. It was also proven that port expansion does not significantly affect drift algae transport in the area. 相似文献
975.
Carlos Navarro Tomás Pérez-Contreras Jesús M. Avilés Kevin J. Mcgraw Juan J. Soler 《Behavioral ecology and sociobiology》2010,64(7):1057-1067
Many colourful sexually selected signals in animals are carotenoid-dependent and, because carotenoids function as antiradicals and immunostimulating molecules, carotenoid-dependent signals may honestly reflect the health state of individuals. Some others nutrients like vitamin A may also enhance health and colouration, but these have rarely been tested alongside carotenoids in colourful birds. Here, we examined whether beak colour of the spotless starling (Sturnus unicolor) reflected circulating levels of carotenoids and/or vitamin A (retinol). Spotless starlings are polygynous, sexually dimorphic birds (i.e. length of chest feathers). The tip of the beaks of male and female spotless starlings is more intensely coloured at the beginning of the breeding season and becomes dull after mating, which may suggest a sexual function. We found that females have a more intensely coloured beak and higher plasma carotenoid concentration than males during mating, and, despite the finding that carotenoid and vitamin A levels were not significantly related; colour intensity was positively correlated with plasma concentration of carotenoids and vitamin A in both sexes. However, adult beak coloration was not associated with carotenoid and vitamin A concentrations after nestlings were hatched. Therefore, beak colouration of spotless starlings provides information about circulating levels of carotenoids and vitamins during the mating season and may potentially function as a reliable signal of physiological status in the context of sexual selection. 相似文献
976.
Coastal development along the Mediterranean coast needs to be tackled with an integrated approach, in order to safeguard people
and properties from extreme events, maintain environmental flows and ecosystems functions, protect coastal landscapes and
ensure public accessibility to the shore. The complexity of the Mediterranean countries legal and administrative framework
and its morphological heterogeneity make the implementation of new the Protocol on ICZM provisions on coastal setbacks,—claiming
for a 100 m wide buffer zone where construction is not allowed— a challenge for the success of the initiative. European countries
and the European Commission are party to the protocol but the European legal framework lacks of specific provisions addressing
the definition of coastal setbacks. Moreover, climate change, in terms of sea level rise and maritime climate, could play
a major role in the future position of setback lines. While arbitrary setbacks should be put in place to halt short-term unwise
coastal development, science can improve the identification of coastal setbacks by providing integrated methodologies to be
implemented at the local level. The objective of this paper is to review concepts and practices in the use of coastal setbacks,
in the context of the provisions of the ICZM protocol and taking into account new challenges posed by climate change. A stepwise
route map is proposed as a base to identify coastal setbacks, applicable to the Mediterranean region and elsewhere, to be
used as a base to improve arbitrary setback approaches. 相似文献
977.
Coastal development along the Mediterranean coast needs to be tackled with an integrated approach, in order to safeguard people
and properties from extreme events, maintain environmental flows and ecosystems functions, protect coastal landscapes and
ensure public accessibility to the shore. The complexity of the Mediterranean countries legal and administrative framework
and its morphological heterogeneity make the implementation of new the Protocol on ICZM provisions on coastal setbacks,—claiming
for a 100 m wide buffer zone where construction is not allowed— a challenge for the success of the initiative. European countries
and the European Commission are party to the protocol but the European legal framework lacks of specific provisions addressing
the definition of coastal setbacks. Moreover, climate change, in terms of sea level rise and maritime climate, could play
a major role in the future position of setback lines. While arbitrary setbacks should be put in place to halt short-term unwise
coastal development, science can improve the identification of coastal setbacks by providing integrated methodologies to be
implemented at the local level. The objective of this paper is to review concepts and practices in the use of coastal setbacks,
in the context of the provisions of the ICZM protocol and taking into account new challenges posed by climate change. A stepwise
route map is proposed as a base to identify coastal setbacks, applicable to the Mediterranean region and elsewhere, to be
used as a base to improve arbitrary setback approaches. 相似文献
978.
Maria Aurélio Filipa Faleiro Vanessa M. Lopes Vanessa Pires Ana Rita Lopes Marta S. Pimentel Tiago Repolho Miguel Baptista Luís Narciso Rui Rosa 《Marine Biology》2013,160(10):2663-2670
The aim of the present study was to evaluate, for the first time, the effect of environmental warming on the metabolic and behavioral ecology of a temperate seahorse, Hippocampus guttulatus. More specifically, we compared routine metabolic rates, thermal sensitivity, ventilation rates, food intake, and behavioral patterns at average spring temperature (18 °C), average summer temperature (26 °C), temperatures that they endure during summer heat wave events (28 °C), and in a near-future warming scenario (+2; 30 °C) in Sado estuary, Portugal. Both newborn juveniles and adults showed significant increases in metabolic rates with rising temperatures. However, newborns were more impacted by future warming via metabolic depression (i.e., heat-induced hipometabolism). In adult stages, ventilation rates also increased significantly with environmental warming, but food intake remained unchanged. Moreover, the frequency of swimming, foraging, swinging, and inactivity did not significantly change between the different thermal scenarios. Thus, we provide evidence that, while adult seahorses show great resilience to heat stress and are not expected to go through any physiological impairment and behavioral change with the projected near-future warming, the early stages display greater thermal sensitivity and may face greater metabolic challenges with potential cascading consequences for their growth and survival. 相似文献
979.
Despite an increase in northern shrimp (Pandalus borealis) female biomass in the past years, the recruitment of the offshore population north and northeast of Iceland has remained very low. In this study, the influence of abiotic and biotic factors was studied in relation to shrimp recruitment. Two factors, cod (Gadus morhua) abundance and summer sea surface temperature (SST), were found to have a negative effect on offshore shrimp recruitment, explaining 71 % of the observed variation. Both cod abundance and temperature on the offshore shrimp grounds have increased in the past years, while recruitment has decreased and been at historically low levels since 2005. No significant relationship was found between recruitment and spawning biomass, indicating that recruitment variability is mainly driven by other factors. Cod abundance and summer SST are likely to affect different life stages of shrimp, as SST influences shrimp during its planktonic phase while cod abundance influences the demersal stage. 相似文献
980.
Júlia Reisser Maíra Proietti Ivan Sazima Paul Kinas Paulo Horta Eduardo Secchi 《Marine Biology》2013,160(12):3169-3179
Feeding ecology of green turtles was investigated between January 2005 and April 2008 at Arvoredo Reserve, Brazil (27°17′S, 48°18′W). Data were obtained through the performance of observational sessions, geo-referenced counts, benthic surveys, capture and recapture of individuals, and oesophageal lavages. This protected area was identified as an important green turtle feeding ground, used year-round by juveniles (curved carapace length = 32–83 cm). Turtles fed close to the rocky shores of the area and selected grazing sites commonly at hard-to-reach, near-vertical portions of the rocks. They were less active in cold months, and more abundant at shallow areas of the reef (0–5 m), where their preferred food items occurred. Their diet was dominated by macroalgae species but invertebrates were also present. Their main food item was the red algae Pterocladiella capillacea, which seems to be eaten through periodical cropping of its tips. Observational methods such as the ones applied here could be incorporated to other research programs aiming to understand the relationships between Chelonia mydas feeding populations and their environment. 相似文献