全文获取类型
收费全文 | 377篇 |
免费 | 3篇 |
国内免费 | 8篇 |
专业分类
安全科学 | 9篇 |
废物处理 | 15篇 |
环保管理 | 63篇 |
综合类 | 76篇 |
基础理论 | 92篇 |
污染及防治 | 101篇 |
评价与监测 | 19篇 |
社会与环境 | 6篇 |
灾害及防治 | 7篇 |
出版年
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 12篇 |
2015年 | 7篇 |
2014年 | 6篇 |
2013年 | 35篇 |
2012年 | 13篇 |
2011年 | 24篇 |
2010年 | 9篇 |
2009年 | 15篇 |
2008年 | 29篇 |
2007年 | 24篇 |
2006年 | 21篇 |
2005年 | 12篇 |
2004年 | 7篇 |
2003年 | 18篇 |
2002年 | 12篇 |
2001年 | 13篇 |
2000年 | 12篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1968年 | 3篇 |
1967年 | 3篇 |
1965年 | 2篇 |
1964年 | 5篇 |
1963年 | 2篇 |
1962年 | 2篇 |
1961年 | 2篇 |
1960年 | 3篇 |
1958年 | 3篇 |
1955年 | 1篇 |
1954年 | 1篇 |
1950年 | 1篇 |
排序方式: 共有388条查询结果,搜索用时 15 毫秒
271.
The diel distribution of feeding activity during the spawning season was compared for territorial male and female cunners Tautogolabrus adspersus in Conception Bay, Newfoundland, Canada between June and August, 1978. Territorial males feed significantly less often than females and concentrate their feeding activities in the morning, whereas females feed as frequently in the afternoon as in the morning. Based on the contents of alimentary tracts, territorial males, non-territorial males, and females have different diets. Since these three groups share the same habitat, the observed dietary differences probably reflect differences in their foraging behaviour. The relevance of these findings to the concept of time minimizer and energy maximizer is discussed. 相似文献
272.
Martins Ajibade Adefisoye Uchechukwu U. Nwodo Ezekiel Green Anthony Ifeanyin Okoh 《Food and environmental virology》2016,8(4):262-274
The occurrence of enteric viruses in reclaimed wastewater, their removal by efficient treatment processes and the public health hazards associated with their release into the environments are of great significance in environmental microbiology. In this study, TaqMan-based real-time polymerase chain reaction (qPCR) was used to assess the prevalence of human adenovirus (HAdV), rotavirus (RV) and hepatitis A virus (HAV) in the final effluents of two wastewater treatment plants in the Eastern Cape Province, South Africa, over a twelve-month sampling period. The correlation between the concentrations of viruses in the effluents samples and faecal coliform (FC) densities were assessed as to validate the use of FC as microbiological indicator in water quality assessment. HAdV was detected in 62.5 % (30/48) of the samples with concentrations ranging between 8.4 × 101 and 1.0 × 105 genome copies/L while HAV and RV were only detected at concentrations below the set detection limits. FCs densities ranged from 1 to 2.7 × 104 CFU/100 ml. Adenovirus species HAdV-B (serotype 2) and HAdV-F (serotype 41) were detected in 86.7 % (26/30) and 6.7 % (2/30) of the HAdV-positive samples, respectively. No consistent seasonal trend was observed in HAdV concentrations, however, increased concentrations of HAdV were generally observed in the winter months. Also, there was no correlation between the occurrence of HAdV and FC at both the treatment plants. The persistent occurrence of HAdV in the discharged treated effluents points to the potential public health risk through the release of HAdV into the receiving watersheds, and the possibility of their transmission to human population. 相似文献
273.
Groundwater Contamination in Karst Terranes 总被引:2,自引:0,他引:2
274.
Mark B. Green Christian H. Fritsen 《Journal of the American Water Resources Association》2006,42(3):659-674
ABSTRACT: Because the Truckee River connects two lakes along the Eastern Sierra Nevada Mountains with different limiting nutrients, this research addresses whether the nitrogen:phosphorus (N:P) balance of the river ecosystem changes longitudinally. Historical (1990 to 2000) total nitro‐gen:total phosphorus (TN:TP) ratios in river water exhibited the expected gradient from high N:P ratios upstream to low N:P ratios downstream, with the major gradient of the N:P balance occurring within the transition between montane and high desert terrain. During 2001, the river contained anomalously low total nitrogen concentrations in the far upper reaches and dissolved inorganic nitrogen concentrations in the lower reaches, resulting in a less apparent longitudinal gradient of N:P ratios. Measurements of periphyton growth and physiology (nutrient bioassays and ectoenzyme activities) and stoichiometry during the summer of 2001 also exhibited a complex picture of the spatial variation of N:P balance that was not entirely consistent with a strong N:P gradient. However, the compendium of the indicators did support the overall picture of an overarching longitudinal gradient from high to low N:P ratios. The results suggest that periphyton management efforts in the Truckee River should consider the overall spatial gradient as well as the small‐scale dynamics of the stream ecosystem structure. 相似文献
275.
Carbon nanotubes (CNTs) have gained substantial interest as a material for biomedical devices with reliable properties suitable for electrically conducting biomedical devices. While CNTs combine ideal properties for a number of tissue-interfacing applications, their biocompatibility and safety have been the source of considerable conjecture. This study outlines a method for evaluating biocompatibility, using a low-cost, short-term assessment model of CNT with primary cells, which are more representative of an in vivo situation than cell lines. It was demonstrated that carboxylate-modified, multi-walled CNTs exhibit cytotoxic behavior in as little as 6 hr of exposure to primary fibroblasts. The resultant cell death was concentration dependent, demonstrating the efficacy of acute assessment of cytocompatibility. Although cell viability remained relatively high (being above 85% for all CNT concentrations up to 500 μg/ml), these results reflect similar relationships found for longer term exposures. This method has reliable potential for high-throughput assessment and quality control of CNTs in biomedical applications using a primary cell model. 相似文献
276.
277.
尽管有很多复杂的模型预测了未来温度对变温动物的影响,广泛分布的亚致命性污染物对变温动物的热应激反应产生的影响却少有模型提及。由不断上升的温度所带来更高的代谢率可以让变温动物获利地加快代谢与发育,但在长期亚致命性污染物的存在下,因清除或解毒而导致的对生存资源的额外需求很可能使得生物难以跟上温度上升的步伐,即毒物诱导的气候敏感性假说。在以自然湖水为背景的室外生物鉴定中,我们调查了一种模式变温动物在6个不同浓度的镉、铜和铅混合物以及3个热动态下(环境温度,高于环境温度1.5摄氏度以及高于环境温度2.5摄氏度)的日周期性温度变化。金属浓度在大约10倍生物可利用性慢性标准单位 (BCCU,慢性标准浓度的生物可利用性比例总和)之下时,升温对于寇普氏树蛙(Hyla chrysoscelis)没有显著作用。在高于10倍BCCU以及高于环境温度1.5摄氏度的处理条件下,生长受到促进。相反地,在28倍BCCU以及升温2.5摄氏度的条件下,不仅生长情况收到抑制,变态后20 d未成年树蛙的身体状况指标相比于背景环境(环境温度下的湖水)中的未成年树蛙也要低34%。这些发现认为毒物诱导的气候敏感性是通过对青少年阶段的生物产生长期潜在的影响而实现的。在22世纪,即使在最保守的全球变暖预测模型下,亚致命性污染物依然会加剧变温动物所遭受的来自升温的影响。
精选自Tyler A. Hallman, Marjorie L. Brooks. Metals-mediated climate susceptibility in a warming world: larval and latent effects on a model amphibian. Environmental Toxicology and Chemistry: Volume 35, Issue 7, pages 1872–1882, July 2016.
DOI: 10.1002/etc.3337
详情请见http://onlinelibrary.wiley.com/doi/10.1002/etc.3337/full 相似文献
278.
Gabriel G. González Katherina B. Brokordt Federico E. Winkler 《Marine Biology》2010,157(10):2195-2203
Several studies on individual physiological traits assume that past records may predict future performance. Marine mollusks,
as other animals, show a wide range of between- and within-individual variation of physiological traits. However, in this
group, almost nothing is known about the relative influence of genetic factors on that variation. Repeatability (R) is a measure of the consistency of the variation of a trait, which includes its genetic variance and represents the maximum
potential value of its heritability (h
2). Traits that show high inter-individual variation and high repeatability levels could potentially evolve through selection
(natural or artificial). We estimated the repeatability [using intra-class (τ) and Pearson-moment (r) correlation coefficients] of several physiological traits related to energy acquisition and allocation in juvenile Pacific
abalone Haliotis discus hannai, maintained under controlled environment growing systems. In order to estimate the range of the R values and the effect of the time elapsed between measurements on these estimates, we measured these traits monthly during
6 months for each individual. Among the physiological traits, those related to energy allocation like oxygen consumption (standard
metabolic rate, SMR) and ammonium excretion rates, and oxygen/nitrogen ratio (O/N), showed intermediate levels of repeatability
(0.48, 0.55 and 0.39, respectively), when this was estimated by τ coefficient. However, the r estimation showed that SMR and O/N repeatability were significant and high (0.6–0.7 and 0.5–0.7, respectively) during the
first 5 consecutive measurements, decreasing strongly (0.3 and 0.2, respectively) during the last measurement. For ammonia
excretion, although repeatability (r) decreased from 0.8 to 0.5 during the 6 consecutive measurements, they remain significant during the experimental period.
Therefore, our results indicate that for H. discus hannai juveniles, physiological traits like SMR, ammonia excretion and O/N are significantly repeatable (i.e. good predictors of
future measurements) during a period of 4–5 months. These significant repeatability values suggest an important genetic control
upon the phenotypic variation of these physiological traits, and could potentially respond to natural or artificial selection,
and be used in genetic improvement programs. By contrast, those traits related to energy acquisition (i.e. ingestion, absorption
and assimilation) and physiological efficiencies (i.e. net growth and scope for growth) showed very low levels of repeatability
(0–0.07). This indicates that the phenotypic variation of these traits would be more influenced by environment rather than
by genetic factors. 相似文献
279.
Om Prakash Stefan J. Green Pooja Singh Puja Jasrotia Joel E. Kostka 《Frontiers of Environmental Science & Engineering》2021,15(2):23
280.
Interlaboratory comparison exercise for the analysis of PCDD/Fs in samples of digested sewage sludge
Joanna L. Stevens Nicholas J. L. Green Russell J. Bowater Kevin C. Jones 《Chemosphere》2001,45(8):1139-1150
Five UK laboratories participated in a study designed to explore the principal sources of interlaboratory variation in the analysis of PCDD/Fs in sewage sludge. Samples of wet sludge, dry sludge, toluene extract of sludge and cleaned extract of sludge were prepared by an organising laboratory. The samples were analysed in duplicate by each laboratory along with a solution of PCDD/F standards and reference sediment. Mean coefficients of variation between laboratories were 45% for the wet sludge, 33% for the dry sludge, 32% for the extract of sludge, 36% for the cleaned extract of sludge, 32% for the reference sediment and 28% for the standard solution. The results were subjected to statistical analysis, which showed that there was no specific part of the analysis that introduced a dominant part of the variation. The spread of data generated from the analysis of wet sludge samples was not appreciably greater than the spread for the analysis of cleaned extracts. Thus the drying, extraction and clean up processes in the PCDD/F analysis of wet sludge did not have a dramatic effect on the interlaboratory variation. 相似文献