全文获取类型
收费全文 | 208篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 2篇 |
废物处理 | 4篇 |
环保管理 | 48篇 |
综合类 | 19篇 |
基础理论 | 66篇 |
污染及防治 | 58篇 |
评价与监测 | 11篇 |
社会与环境 | 3篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2017年 | 6篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 18篇 |
2012年 | 4篇 |
2011年 | 11篇 |
2010年 | 6篇 |
2009年 | 4篇 |
2008年 | 9篇 |
2007年 | 5篇 |
2006年 | 6篇 |
2005年 | 13篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 6篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1983年 | 4篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1967年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有214条查询结果,搜索用时 15 毫秒
21.
Predicting Opportunities for Greening and Patterns of Vegetation on Private Urban Lands 总被引:1,自引:1,他引:1
Troy AR Grove JM O'Neil-Dunne JP Pickett ST Cadenasso ML 《Environmental management》2007,40(3):394-412
This paper examines predictors of vegetative cover on private lands in Baltimore, Maryland. Using high-resolution spatial
data, we generated two measures: “possible stewardship,” which is the proportion of private land that does not have built
structures on it and hence has the possibility of supporting vegetation, and “realized stewardship,” which is the proportion
of possible stewardship land upon which vegetation is growing. These measures were calculated at the parcel level and averaged
by US Census block group. Realized stewardship was further defined by proportion of tree canopy and grass. Expenditures on
yard supplies and services, available by block group, were used to help understand where vegetation condition appears to be
the result of current activity, past legacies, or abandonment. PRIZM™ market segmentation data were tested as categorical
predictors of possible and realized stewardship and yard expenditures. PRIZM™ segmentations are hierarchically clustered into
5, 15, and 62 categories, which correspond to population density, social stratification (income and education), and lifestyle
clusters, respectively. We found that PRIZM 15 best predicted variation in possible stewardship and PRIZM 62 best predicted
variation in realized stewardship. These results were further analyzed by regressing each dependent variable against a set
of continuous variables reflective of each of the three PRIZM groupings. Housing age, vacancy, and population density were
found to be critical determinants of both stewardship metrics. A number of lifestyle factors, such as average family size,
marriage rates, and percentage of single-family detached homes, were strongly related to realized stewardship. The percentage
of African Americans by block group was positively related to realized stewardship but negatively related to yard expenditures. 相似文献
22.
23.
24.
Gabrielle Ednie Tyreen Kapoor Olga Koppel Morgan L. Piczak Jessica L. Reid Alyssa D. Murdoch Carly N. Cook William J. Sutherland Steven J. Cooke 《Ambio》2023,52(2):411
Foresight science is a systematic approach to generate future predictions for planning and management by drawing upon analytical and predictive tools to understand the past and present, while providing insights about the future. To illustrate the application of foresight science in conservation, we present three case studies: identification of emerging risks to conservation, conservation of at-risk species, and aid in the development of management strategies for multiple stressors. We highlight barriers to mainstreaming foresight science in conservation including knowledge accessibility/organization, communication across diverse stakeholders/decision makers, and organizational capacity. Finally, we investigate opportunities for mainstreaming foresight science including continued advocacy to showcase its application, incorporating emerging technologies (i.e., artificial intelligence) to increase capacity/decrease costs, and increasing education/training in foresight science via specialized courses and curricula for trainees and practicing professionals. We argue that failure to mainstream foresight science will hinder the ability to achieve future conservation objectives in the Anthropocene.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-022-01786-0. 相似文献
25.
Slugs (Deroceras reticulatum and Arion subfuscus) were sampled from two distinct sites, an uncontaminated site at Dinas Powys and a Pb-contaminated, disusedmine site at Llantrisant. Batches of the slugs were exposed for ten days under laboratory conditions to an artificial diet consisting of a 5% (w/v) agar + 5% (w/v) sucrose matrix contaminated with different concentrations of Pb, as Pb (NO(3))(2). The food 'cubes' contained approximately 0, 10, 100, and 1000 microg Pb ml(-1). Tissue-Pb concentrations increased with increasing dietary-Pb concentration in both species. However, at the highest Pb exposure (1000 microg ml(-1)) the tissue-Pb concentrations in D. reticulatum and A. subfuscus sampled originally from the clean site were higher than those in their counterparts from the contaminated site, even though the Llantrisant slugs had significantly higher baseline Pb concentrations than the Dinas Powys slugs. It is suggested that these observations indicate metal tolerance phenotypically expressed as reduced accumulation in the populations with a history of Pb-exposure in their natural habitat. We discuss how biomonitoring may be affected by the way in which different slug populations deal with metals. 相似文献
26.
27.
John D. Morgan 《Resources Policy》1980,6(1):33-43
In 1978 the USA used non-fuel processed mineral materials valued at over $200 billion (109). Non-fuel mineral imports caused a trade imbalance of $8 billion. Imports supplied more than half of US supplies of 20 important minerals. The US stockpile of strategic materials is valued at over $11 billion. While world reserves of most minerals are now deemed adequate until 2000, demand for high temperature and special property materials requires careful monitoring and anticipation of disruptions in vulnerable sources. 相似文献
28.
An investigation of gametogenetic cycles and spawning success in populations of Nephtys caeca and N. hombergi from the River Tyne estuary, North Shields, England, in relation to production of gonadotrophic (GH) and spawning hormones (SH) has been made, based on data collected from 1978–1984. The data show that a consistent pattern of gametogenesis and efficient spawning occurs in populations of N. caeca in north-east England, but that the reproductive cycle of N. hombergi is erratic. Premature oosorption and gametogenic failure in this latter species is associated with a low level of GH production. Following high levels of GH production, gravid females sometimes fail to spawn owing to the non-release of SH. The reproductive energetics and reproductive success of N. caeca and N. hombergi are described in relation to the observed patterns of endocrine activity and the consequent changes in population structure. 相似文献
29.
Many agricultural, biological, and environmental studies involve detecting temporal changes of a response variable, based on data observed at sampling sites in a spatial region and repeatedly over several time points. That is, data are repeated measures over time and are potentially correlated across space. The traditional repeated-measures analysis allows for time dependence but assumes that the observations at different sampling sites are mutually independent, which may not be suitable for field data that are correlated across space. In this paper, a nonparametric large-sample inference procedure is developed to assess the time effects while accounting for the spatial dependence using a block bootstrap. For illustration, the methodology is applied to describe the population changes of root-lesion nematodes over time in a production field in Wisconsin. 相似文献
30.
Isozyme changes in the xanthid crab Rhithropanopeus harrisii (Gould) are described for 6 enzyme systems through all four zoeal stages, megalopa stage, and juveniles. There is considerable variation in the number of isozymes and their expression during the ontogeny of R. harrisii.Contribution No. 806 of the Chesapeake Biological Laboratory, Center for Environmental and Estuarine Studies, University of Maryland, USA. 相似文献