首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   761篇
  免费   10篇
  国内免费   13篇
安全科学   12篇
废物处理   38篇
环保管理   84篇
综合类   88篇
基础理论   204篇
环境理论   1篇
污染及防治   242篇
评价与监测   67篇
社会与环境   41篇
灾害及防治   7篇
  2023年   12篇
  2022年   31篇
  2021年   33篇
  2020年   19篇
  2019年   12篇
  2018年   26篇
  2017年   37篇
  2016年   35篇
  2015年   27篇
  2014年   56篇
  2013年   75篇
  2012年   37篇
  2011年   54篇
  2010年   52篇
  2009年   37篇
  2008年   38篇
  2007年   47篇
  2006年   32篇
  2005年   17篇
  2004年   21篇
  2003年   21篇
  2002年   14篇
  2001年   6篇
  2000年   4篇
  1999年   4篇
  1998年   6篇
  1997年   7篇
  1996年   1篇
  1995年   3篇
  1994年   3篇
  1993年   2篇
  1992年   4篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1985年   2篇
  1984年   1篇
  1978年   1篇
  1957年   1篇
排序方式: 共有784条查询结果,搜索用时 390 毫秒
561.
We compiled 46 broadscale data sets of species richness for a wide range of terrestrial plant, invertebrate, and ectothermic vertebrate groups in all parts of the world to test the ability of metabolic theory to account for observed diversity gradients. The theory makes two related predictions: (1) In-transformed richness is linearly associated with a linear, inverse transformation of annual temperature, and (2) the slope of the relationship is near -0.65. Of the 46 data sets, 14 had no significant relationship; of the remaining 32, nine were linear, meeting prediction 1. Model I (ordinary least squares, OLS) and model II (reduced major axis, RMA) regressions then tested the linear slopes against prediction 2. In the 23 data sets having nonlinear relationships between richness and temperature, split-line regression divided the data into linear components, and regressions were done on each component to test prediction 2 for subsets of the data. Of the 46 data sets analyzed in their entirety using OLS regression, one was consistent with metabolic theory (meeting both predictions), and one was possibly consistent. Using RMA regression, no data sets were consistent. Of 67 analyses of prediction 2 using OLS regression on all linear data sets and subsets, two were consistent with the prediction, and four were possibly consistent. Using RMA regression, one was consistent (albeit weakly), and four were possibly consistent. We also found that the relationship between richness and temperature is both taxonomically and geographically conditional, and there is no evidence for a universal response of diversity to temperature. Meta-analyses confirmed significant heterogeneity in slopes among data sets, and the combined slopes across studies were significantly lower than the range of slopes predicted by metabolic theory based on both OLS and RMA regressions. We conclude that metabolic theory, as currently formulated, is a poor predictor of observed diversity gradients in most terrestrial systems.  相似文献   
562.
Although vast literature exists on the drivers of tropical deforestation and its ecological consequences, less is known about how patterns of forest fragmentation emerge in the first place. The purpose of this paper is to address this issue for the Brazilian portion of the Amazon basin by analyzing the social processes generative of five specific patterns, including rectangular, fishbone, radial, dendritic, and what we refer to as ‘the stem of the rose.’ We argue that forest fragmentation patterns in the Brazilian Amazon are largely determined by the types and arrival times of the agents who engage in land clearing. We also argue that the patterns manifest in the landscape by virtue of road construction and agricultural property formation, which often occur in tandem. We conclude by placing our discussion within legal and institutional contexts, and observe that fragmentation stemming from formal colonization projects is more consistent with biodiversity conservation than that associated with a laissez-faire occupation. However, erosive impacts may be greater in topographically sensitive areas.  相似文献   
563.
Exposure to uranium (U) is an occupational hazard to workers who continually handle it and an environmental risk to the population at large. Adverse effects of U on different tissues, particularly kidneys, have been reported. The aim of the present study was to investigate whether U might produce damage to the rat submandibular gland (SMG). Uranyl nitrate (UN) was used to evaluate the secretory responses to norepinephrine (NE) or to the parasympathomimetic agent, methacholine (MC), along with some morphological and histological parameters. In addition, the presence of U in saliva was determined by atomic absorption spectrometric techniques. Results indicate that intraperitoneal (i.p.) injection of a single dose of UN (2 or 4 mg kg?1) induced a functional decrease in the induced secretory responses in the rat SMG, demonstrating for the first time that U interferes with salivary secretion. Moreover, salivary responses to MC as well as to NE were decreased after UN administration, in time- and dose-dependent manner, displaying a higher diminution after 7 days post injection. In agreement with the functional studies, the injection of UN produced morphological alterations of SMG, consisting in a reduction of mean acinar area and a marked vacuolization. Data indicate that UN produced an adverse effect in a dose- and time-dependent manner on SMG function and morphology. Furthermore, it was shown that U was incorporated in saliva and therefore, these findings may contribute to create a useful, noninvasive method to detect the exposure to U.  相似文献   
564.
Glyphosate is the most used pesticide in Argentina. Hyalella curvispina is a widely distributed and commonly abundant component of the invertebrate assemblages in shallow waters of southern South America. The aim of this study was to assess the acute toxicity of the increasingly common Roundup Full II®, commercial formulation of the herbicide glyphosate (66.2% active ingredient), to H. curvispina in laboratory and field assessments. The mean estimated 48-h LC50 of Roundup was 9.9 ± 1.7 mg L?1. In a field experiment Roundup was applied to soybean plots. Simulated rain was generated the following day by means of irrigation sprinkler equipment. H. curvispina was exposed to runoff water and soy leaves. No mortality was observed. It is suggested that Roundup crop applications represent a low risk of acute toxicity to H. curvispina adults inhabiting water bodies adjacent to crop fields.  相似文献   
565.
Indigenous populations have lived for many generations in a sustainable fashion, developing knowledge about how to live in harmony with the environment. However, the sustainability of their life styles, their quality of life and the maintenance of intact ecosystems are threatened by a series of changes, including incorporation into the general fabric of society, conflict with non-indigenous migrants, expansion of indigenous populations and the globalization of national economies. This paper looks at the potential for policy to deal with these issues. In particular, it is shown that the ‘polluter pays principle’ is not appropriate for indigenous societies. The paper recommends a set of policies and shows how international cooperation in the areas of monitoring and enforcement, augmentation of demand for rain forest products and eco-certification can help indigenous groups improve their quality of life and maintain ecosystems in their current undisturbed state.  相似文献   
566.
Local residents may have different views on disaster‐response modes depending on their cultural and socioeconomic background. The purpose of this study was to examine Taiwan residents' opinions on the Incident Command System (ICS). We performed a structured survey through face‐to‐face interviews in mudslide‐affected communities. Quantitative analysis showed that the residents exhibited a clear preference for the ICS core‐principle attributes of ‘integrated communications’, ‘transfer of command’ and ‘modular organisation’. By contrast, the residents tended towards a non‐ICS approach for ‘incident action plan’ and ‘manageable span of control’. Qualitative analysis revealed an uncertain attitude towards ‘transfer of command’ and ‘incident action plan’. Community acceptance is important in the promotion of the ICS. A better understanding of residents' preferences should be acquired through a broader community survey, allowing us to understand perspectives on the ICS among different societies and facilitate implementation of the ICS at the basic community level.  相似文献   
567.
The brown mussel Perna perna (Linnaeus, 1758) is a valuable resource for aquaculture in tropical and subtropical coastal regions. It presents desirable characteristics for biomonitoring, including being sessile, widely distributed and abundant, and is a filter-feeder able to accumulate several classes of pollutants (e.g., metals, hydrocarbons, among others). Mussels’ biological responses to pollution exposure can be measured as biomarkers, which include alterations ranging from molecular to physiological levels, to estimate the degree of environmental contamination and its effects on biota. This full review compiles two decades (2000–2020) of literature concerning biological effects on P. perna mussel caused by environmental pollutants (i.e., metals, hydrocarbons, and emerging pollutants), considering environmental and farm-based biomonitoring. Biochemical markers related to mussels’ oxidative status were efficient for the biomonitoring of metals (i.e., antioxidant enzymes associated with oxidative damage in biomolecules). Genotoxicity and cytotoxicity indicators (i.e., comet, micronucleus, and neutral red assays) provided a depiction of hydrocarbon contamination. The neutral red assay gave a time-concentration cytotoxic response to a wide range of pollutants, including emerging pollutants (e.g., pharmaceuticals and biocides) and hydrocarbons. Perna perna hemocyte parameters provided a useful approach for biocide biomonitoring. This paper summarizes useful biomarkers from molecular to physiological levels in this mussel species used to identify and quantify the degree of coastal pollution. An integrated biomarker analysis may provide a way to overcome possible biomarker variations and assess multi-polluted sites. Nevertheless, it is necessary to investigate biomarker variations according to natural factors (e.g., season and gonad maturation stage) to standardize them for trustworthy biomonitoring.  相似文献   
568.
Environmental Science and Pollution Research - The objective of this study is to compare the environmental and social performance of two small-scale avocado biorefineries implanted in a rural zone...  相似文献   
569.
Comprehensive biodiversity assessments play an essential role in strengthening global and national conservation strategies. The recently announced first U.S. National Nature Assessment (NNA) provides an unparalleled opportunity to comprehensively review status and trends of biodiversity at all levels. This broad context can help in the coordination of actions to conserve individual species and ecosystems. The scientific assessments that informed the Kunming–Montreal Global Biodiversity Framework adopted at the 2022 Convention on Biological Diversity (CBD) conference of parties provide models for synthesizing information on trends at multiple levels of biodiversity, including decline in abundance and distribution of species, loss of populations and genetic diversity, and degradation and loss of ecosystems and their services. The assessments then relate these trends to data on drivers of biodiversity loss and pathways to their mitigation. The U.S. NNA can augment such global analyses and avoid the pitfalls encountered by previous U.S. efforts by ensuring policy-relevant design, data accessibility, and inclusivity in process and product and by incorporating spatial data relevant to national and subnational audiences. Although the United States is not formally a CBD party, an effective NNA should take full advantage of the global context by including indicators adopted at the 2022 meeting and incorporating an independent review mechanism that supports periodic stocktaking and ratcheting up of ambition in response to identified shortfalls in stemming biodiversity loss. The challenges to design of an effective U.S. assessment are relevant globally as nations develop assessments and reporting to support the new global biodiversity framework's targets. By considering and incorporating the diverse ways in which society values and benefits from nature, such assessments can help bridge the gap between research and conservation practice and communicate the extent of the biodiversity crisis to the public, fostering broad-based support for transformative change in humanity's relationship to the natural world.  相似文献   
570.
Enforcement gaps are an especially vexing problem in China due to pervasive "pro-growth" local government priorities, the weak administrative capacity of environmental agencies themselves, and relatively weak levels of societal support for a cleaner environment. This study seeks to examine this problem from the perspective of the local enforcement officials by empirically examining the relationships between these and other influences on their perceptions of enforcement effectiveness. Using samples of enforcement officials from the fast-growing cities of Chengdu, Dalian, and Guangzhou, this study finds that many of the more commonly cited problems related to regulatory enforcement were not as influential in accounting for variations in perceptions of enforcement effectiveness than the current literature might suggest. Moreover, this study also finds that the pattern of influences varies greatly across jurisdictions, with only the officials' belief in the legitimacy of the governments' policies being significant in all three samples. Strong influences on perceptions of enforcement effectiveness in two of the three samples include the environmental values of enforcement officials, their perceptions of organizational capacity for enforcement, and their assessment of government support for environmental protection. Although government support was found to be a strong predictor of enforcement effectiveness in two of the three samples, the influence of societal support had a somewhat mixed and more complicated effect. In addition, this study suggests that further improvements in enforcement effectiveness may be possible by cultivating or selecting enforcement officials with strong environmental values and beliefs in the legitimacy of the government's environmental policy to take charge of enforcement. Because it is generally accepted that local environmental protection bureaus are generally upgrading their organizational capacity for improvement as the result of increasing central government support for environmental protection and institutional restructuring, and because environmental awareness in China is growing, this study suggests that some incremental progress is likely in China's efforts to close the enforcement gap. Unfortunately, such improvements are likely to be masked by the steep trajectory of economic growth, the narrow scope of regulatory control (i.e., with scant attention paid to nonindustrial sources), and the migration of industrial pollution to rural areas.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号