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   107篇
  免费   4篇
安全科学   3篇
废物处理   5篇
环保管理   16篇
综合类   21篇
基础理论   22篇
污染及防治   25篇
评价与监测   5篇
社会与环境   5篇
灾害及防治   9篇
  2023年   2篇
  2021年   2篇
  2020年   1篇
  2019年   1篇
  2018年   4篇
  2017年   2篇
  2016年   8篇
  2015年   2篇
  2014年   9篇
  2013年   13篇
  2012年   2篇
  2011年   7篇
  2010年   4篇
  2009年   7篇
  2008年   10篇
  2007年   6篇
  2006年   3篇
  2005年   4篇
  2004年   2篇
  2003年   5篇
  2002年   1篇
  2001年   2篇
  2000年   2篇
  1998年   2篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   1篇
  1990年   1篇
  1989年   1篇
  1981年   1篇
  1957年   1篇
排序方式: 共有111条查询结果,搜索用时 125 毫秒
61.
The fossil record of late Campanian tyrannosauroids of western North America has a geographic gap between the Northern Rocky Mountain Region (Montana, Alberta) and the Southwest (New Mexico, Utah). Until recently, diagnostic tyrannosauroids from the Southwest were unknown until the discovery of Bistahieversor sealeyi from the late Campanian of New Mexico. Here we describe an incomplete skull and postcranial skeleton of an unusual tyrannosaurid from the Kaiparowits Formation (Late Cretaceous) of Utah that represents a new genus and species, Teratophoneus curriei. Teratophoneus differs from other tyrannosauroids in having a short skull, as indicated by a short and steep maxilla, abrupt angle in the postorbital process of the jugal, laterally oriented paroccipital processes, short basicranium, and reduced number of teeth. Teratophoneus is the sister taxon of the Daspletosaurus + Tyrannosaurus clade and it is the most basal North American tyrannosaurine. The presence of Teratophoneus suggests that dinosaur faunas were regionally endemic in the west during the upper Campanian. The divergence in skull form seen in tyrannosaurines indicates that the skull in this clade had a wide range of adaptive morphotypes.  相似文献   
62.
Just as a stream of genetically modifiedcrops looked set to be approved for commercialproduction in the European Union, the approvalprocedure appears to have become bogged down onceagain by disagreements among and within member states.Old controversies have resurfaced in new forms. Theintractability of the issues suggests that theregulatory procedure has had too narrow a focus,leaving outside its boundary many of the morefundamental aspects that cause people in the EuropeanUnion most concern. Regulators have come underconsiderable pressure to ensure their risk assessmentdecisions are soundly science-based. Ethical issueshave been deemed to lie beyond the scope of theregulatory procedure, as a matter to be consideredseparately by professional ethicists. Yet it has beensuggested that all environmental controversies at rootinvolve disputes about fundamental ethical principles.This paper examines how the ethical issues arecurrently suppressed or sidelined. It discusses how anappreciation of systems thinking and a check on thevalues that underpin decisions, using boundary testingquestions, might contribute to a more constructiveregulatory dialogue, with ethical issues considered asintegral in a way that takes better account ofpeople's concerns.  相似文献   
63.
Data from toxicity tests of the pore water extracted from Puget Sound sediments were compiled from surveys conducted from 1997 to 2009. Tests were performed on 664 samples collected throughout all of the eight monitoring regions in the Sound, an area encompassing 2,294.1 km2. Tests were performed with the gametes of the Pacific purple sea urchin, Strongylocentrotus purpuratus, to measure percent fertilization success as an indicator of relative sediment quality. Data were evaluated to determine the incidence, degree of response, geographic patterns, spatial extent, and temporal changes in toxicity. This is the first survey of this kind and magnitude in Puget Sound. In the initial round of surveys of the eight regions, 40 of 381 samples were toxic for an incidence of 10.5 %. Stations classified as toxic represented an estimated total of 107.1 km2, equivalent to 4.7 % of the total area. Percent sea urchin fertilization ranged from >100 % of the nontoxic, negative controls to 0 %. Toxicity was most prevalent and pervasive in the industrialized harbors and lowest in the deep basins. Conditions were intermediate in deep-water passages, urban bays, and rural bays. A second round of testing in four regions and three selected urban bays was completed 5–10 years following the first round. The incidence and spatial extent of toxicity decreased in two of the regions and two of the bays and increased in the other two regions and the third bay; however, only the latter change was statistically significant. Both the incidence and spatial extent of toxicity were lower in the Sound than in most other US estuaries and marine bays.  相似文献   
64.
The concentrations of selected polychlorinated naphthalene (PCN) congeners (PCNs 52, 53, 66/67, 68, 69, 71/72, 73, 74 and 75) were determined in 100 commonly consumed foods, in the first study on occurrence of these contaminants in the Republic of Ireland. Congener selection was based on current knowledge on PCN occurrence and toxicology, and the availability of reliable reference standards. The determinations were carried out using validated analytical methodology based on 13C10 labelled internal standardisation and measurement by HRGC-HRMS. The results showed PCN occurrence in the majority of studied foods--milk, fish, dairy and meat products, eggs, animal fat, shellfish, offal, vegetables, cereal products, etc. ranging from 0.09 ng kg(-1) whole weight for milk to 59.3 ng kg(-1) whole weight for fish, for the sum of the measured PCNs. The most frequently detected congeners were PCNs 66/67, PCN 52, and PCN 73. The highest concentrations were observed in fish, which generally showed congener profiles that reflect some commercial mixtures. The data compares well with other recently reported data for Western Europe. The dioxin-like toxicity (PCN TEQ) associated with these concentrations is lower than that reported for chlorinated dioxins or PCBs in food from Ireland. The dietary exposure of the Irish adult population to PCNs was calculated following a probabilistic approach, using the full dataset of occurrence and current consumption data. The estimates of dietary intakes at approximately 0.14 pg TEQ kg bw(-1) month(-1) for adults on an average diet, reflects the relatively lower occurrence levels.  相似文献   
65.
Currently, 1.5 million homes in Texas, USA utilize an on-site sewage facility to manage their household waste. This study compares the conventional septic dispersal technology of perforated pipe drain field with two of the new technologies recently implemented in Texas, multi-pipe and chamber systems, determining if soil classification and climate are influencing factors in functional ability for each of the technologies. There is no statistical significance for failure of a system with respect to system type or climate zone. The textural classification of soil is a statistically significant variable in septic system failures. Soil type III, which includes the clay groups except pure clays and silty clay, appears to significantly influence system failures. Additionally, occupant misuse and lack of maintenance are contributing factors to system failure.  相似文献   
66.
This paper is a response to a recent special issue of Regional Environmental Change, “Quantifying vulnerability to drought from different disciplinary perspectives” (vol. 8, number 4, 2008). In this paper, we examine some of the challenges facing efforts to understand vulnerability to drought through quantification as they are manifest in some of the articles in this special issue.
Edward R. CarrEmail:
  相似文献   
67.
Most current approaches focused on vulnerability, resilience, and adaptation to climate change frame gender and its influence in a manner out-of-step with contemporary academic and international development research. The tendency to rely on analyses of the sex-disaggregated gender categories of ‘men’ and ‘women’ as sole or principal divisions explaining the abilities of different people within a group to adapt to climate change, illustrates this problem. This framing of gender persists in spite of established bodies of knowledge that show how roles and responsibilities that influence a person´s ability to deal with climate-induced and other stressors emerge at the intersection of diverse identity categories, including but not limited to gender, age, seniority, ethnicity, marital status, and livelihoods. Here, we provide a review of relevant literature on this topic and argue that approaching vulnerability to climate change through intersectional understandings of identity can help improve adaptation programming, project design, implementation, and outcomes.  相似文献   
68.
A methodology is proposed to complement the subjective “value” of intelligence with an objective metric of “impact” of information on network models. This is a deterministic one-way sensitivity analysis similar to value of information used in inference diagrams. It would measure the impact of a piece of information on a network’s metric, in this case being used to answer intelligence analyst questions. This methodology suggests that the sensitivity of each link to existing analysis implies that the link has an impact on the analysis. The impact of these links can be measured quantitatively. In this paper, we explore data of tweets and apply the methodology to the links between twitter users and use the network measure of betweenness centrality to determine their quantitative impact on the overall network.  相似文献   
69.
Developing a globally responsive Science‐Practitioner‐Humanist model (Lefkowitz, 2008 ) means articulating professional values (supply) and meeting global demand. The United Nations' Millennium Development Goals (MDGs) seek to halve human poverty by 2015 and how organizations respond to this constitutes a formidable demand on Organizational Psychology. A key process for delivering more effective aid is the Paris Declaration on Aid Effectiveness, which seeks collaborative contributions from a plethora of Organizations, including business organizations and professions like ours. We argue that a thoughtful articulation of what Organizational Psychology uniquely stands for, and can offer, is therefore needed. It is proposed that a key mechanism for addressing this challenge is a Task Force, whose functions will include the coordination of institutions within psychology, and linking them to those in development. We describe such a task force and outline its core mission (Reichman, Frese, Schein, Carr, MacLachlan, & Landy, 2008 ). Organizational Psychology's response to poverty reduction should meet Lefkowitz's criteria for developing a more humanist model of science and practice as the MDGs are inherently humanist and values‐based. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
70.
Kelman I 《Disasters》2007,31(3):288-309
Hurricane Katrina struck the United States at the end of August 2005. The consequent devastation appeared to be beyond the US government's ability to cope with and aid was offered by several states in varying degrees of conflict with the US. Hurricane Katrina therefore became a potential case study for 'disaster diplomacy', which examines how disaster-related activities do and do not yield diplomatic gains. A review of past disaster diplomacy work is provided. The literature's case studies are then categorised using a new typology: propinquity, aid relationship, level and purpose. Hurricane Katrina and its aftermath are then placed in the context of the US government's foreign policy, the international response to the disaster and the US government's reaction to these responses. The evidence presented is used to discuss the potential implications of Hurricane Katrina disaster diplomacy, indicating that factors other than disaster-related activities generally dominate diplomatic relations and foreign policy.  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