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   106篇
  免费   1篇
安全科学   10篇
废物处理   1篇
环保管理   36篇
综合类   7篇
基础理论   24篇
污染及防治   18篇
评价与监测   7篇
社会与环境   2篇
灾害及防治   2篇
  2023年   2篇
  2022年   1篇
  2021年   2篇
  2020年   3篇
  2019年   1篇
  2018年   1篇
  2017年   6篇
  2016年   4篇
  2015年   2篇
  2014年   2篇
  2013年   7篇
  2012年   5篇
  2011年   5篇
  2010年   5篇
  2009年   5篇
  2008年   1篇
  2007年   10篇
  2006年   5篇
  2005年   2篇
  2003年   1篇
  2002年   3篇
  2000年   3篇
  1997年   2篇
  1996年   1篇
  1995年   2篇
  1994年   3篇
  1993年   1篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1982年   3篇
  1981年   5篇
  1974年   2篇
  1973年   1篇
排序方式: 共有107条查询结果,搜索用时 15 毫秒
101.
G. Freeman 《Marine Biology》1987,93(4):535-541
The base of the tentacle of the developing physonect larva (Nanomia cara) has a bioluminescent region. The ability to produce light in the larva is transitory; this ability first appears at about two days of development and is disappearing by eight days, as the larva begins to feed. Subsequently paired bilaterally symmetrical bioluminescent organs are found on the nectophores and the bracts of the adult colony. In both the larva and the adult, bioluminescence is mediated by a calcium specific photoprotein. In all cases the photocytes lack a green fluorescent protein.  相似文献   
102.
Summary Perhaps the most important factor affecting predator-prey interactions is their encounter probability. Predators must either locate sites where prey are active or attract prey to them, and prey must be able to recognize potential predators and flee before capture. In this study we manipulate and describe three components of the foraging system of predatory, web-weaving spiders, the presence of viscid droplets, silk brightness (achromatic surface reflectance), and visibility of the orb pattern, to determine their effect on insect attraction, recognition, and web avoidance. We found that webs with viscid droplets were more visible to prey at close range, but at greater distances the sparkling droplets lured insects to the web area and hence increased insect capture probability. Although the size of viscid droplets and silk brightness are closely correlated (Table 2, Fig. 3), the relationships among droplet size, spider size, and the visual environments in which webs are found are more complicated (Fig. 2, Tables 2, 3). In environments with predictable light exposure, droplet size and hence silk visibility correlate with spider size, and spiders that forage at night produce relatively more visible silks then spiders that forage during the day (Table 3, Fig. 4). In habitats in which light levels are not predictable, silk surface reflectance and spider size are not closely correlated, suggesting that the complexity of the light environment, as well as the visual and foraging behaviors of insects found there, has played an important role in the evolution of spider-insect interactions.Offprint requests to: C.L. Craig  相似文献   
103.
U.S. Forest Service managers are required to incorporate social and biophysical science information in planning and environmental analysis. The use of science is mandated by the National Environmental Policy Act, the National Forest Management Act, and U.S. Forest Service planning rules. Despite the agency’s emphasis on ‘science-based’ decision-making, little is known about how science is actually used in recreation planning and management. This study investigated the perceptions of Forest Service interdisciplinary (ID) team leaders for 106 NEPA projects dealing with recreation and travel management between 2005 and 2008. Our survey data show how managers rate the importance of social and biophysical science compared to other potential ‘success factors’ in NEPA assessments. We also explore how team leaders value and use multi-disciplinary tools for recreation-related assessments. Results suggest that managers employ a variety of recreation planning tools in NEPA projects, but there appears to be no common understanding or approach for how or when these tools are incorporated. The Recreation Opportunity Spectrum (ROS) was the most frequently used planning tool, but the Visitor Experience and Resource Protection (VERP) framework was the most consistently valued tool by those who used it. We recommend further evaluation of the strengths and weaknesses of each planning tool and future development of procedures to select appropriate planning tools for use in recreation-related NEPA assessments.  相似文献   
104.
We employed qualitative methods to explore how conflict over water collection and use impacts women, and the role that women play in water management and conflict resolution in Marsabit, Kenya. Conflicts between domestic and livestock water led to insufficient water for domestic use and intra-household conflict. Women’s contributions to water management were valued, especially through informal initiatives, though involvement in statutory water management committees was not culturally appropriate. Promoting culturally appropriate ways to involve women in water management, rather than merely increasing the percentage of women on water committee, may reduce conflicts and increase women’s access to domestic water supplies.  相似文献   
105.
OBJECTIVE: This is a study of 8,464 adult women and 21,155 adult males who entered substance abuse treatment in Texas between 2000 and 2005. Participants were either on probation for driving under the influence (DUI), were referred to treatment by DUI probation, or had been arrested for DUI in the past year. METHODS: The female and male clients were compared on demographic characteristics, substance use patterns, DSM-IV diagnoses, and levels of impairment. T tests and chi square tests were used to determine significance and multivariate logistic regression identified predictors of completing treatment and being abstinent at follow-up. RESULTS: The proportion of females who were sent to treatment as a result of DUI increased from 27% in 2000 to 32% in 2005. Females were significantly more likely than males to be White (73% vs. 56%), to have used substances a shorter period of time (17 vs. 19 years), to be seeking custody to regain their children (11% vs. 2%), to meet the DSM criteria for drug dependence (32% vs. 23%), to have injected drugs (31% vs. 23%), to have used substances daily (42% vs. 40%), to have a depressive disorder (16% vs. 7%) or bipolar disorder (12% vs. 5%), and to be have been in treatment before (60% vs. 49%). In contrast, males were more likely to be alcohol dependent (49% vs. 44%). Females were less likely to complete treatment (67% vs. 72%) and reported significantly more days of problems on the 6 domains of the ASI at both admission and at 60-day follow-up. Furthermore, at follow-up, they were more likely to be living with someone who abused alcohol or used drugs (9% vs.7%). CONCLUSIONS: Although females comprised only 29% of the DUI treatment admissions, they were more impaired and experienced more problems than their male counterparts. The findings indicate that additional resources, including treatment for co-occurring mental health problems and living in sober households, may be keys to helping these women achieve abstinence and prevent additional DUI episodes.  相似文献   
106.
107.
ABSTRACT: Water policy problems are wicked, not in an ethically deplorable sense, but in the sense that they present us with especially difficult challenges of becoming more effective in our interdisciplinary collaboration, of integrating two very different types of knowledge, of working across several socio‐political units of analysis simultaneously, and of better organizing water as a common property resource. Sociology, as a discipline, does not have a particularly rich history of successful interdisciplinary collaboration on water resources research and teaching, but it potentially has a most useful contribution to make by focusing on the analysis of local common property resource organizations that operate in the interface between individual resource users and State‐Federal entities. These organizations (e.g., water user associations, mutual companies, irrigation districts, acequias, conservancy districts) have been the orphans of water policy discourse but their operations are critical to undertaking more effective 21st century social analysis, research work, and action programs. Sociologists who work to better comprehend the operations of, and constraints upon, these organizations build a sociology that can better collaborate with other water‐related disciplines in addressing the challenges posed by the wickedness of our water problems.  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