全文获取类型
收费全文 | 986篇 |
免费 | 43篇 |
国内免费 | 12篇 |
专业分类
安全科学 | 39篇 |
废物处理 | 45篇 |
环保管理 | 268篇 |
综合类 | 83篇 |
基础理论 | 243篇 |
环境理论 | 1篇 |
污染及防治 | 266篇 |
评价与监测 | 60篇 |
社会与环境 | 29篇 |
灾害及防治 | 7篇 |
出版年
2023年 | 6篇 |
2022年 | 8篇 |
2021年 | 9篇 |
2020年 | 17篇 |
2019年 | 4篇 |
2018年 | 24篇 |
2017年 | 29篇 |
2016年 | 29篇 |
2015年 | 26篇 |
2014年 | 31篇 |
2013年 | 96篇 |
2012年 | 40篇 |
2011年 | 51篇 |
2010年 | 39篇 |
2009年 | 46篇 |
2008年 | 56篇 |
2007年 | 56篇 |
2006年 | 54篇 |
2005年 | 38篇 |
2004年 | 34篇 |
2003年 | 36篇 |
2002年 | 37篇 |
2001年 | 17篇 |
2000年 | 27篇 |
1999年 | 16篇 |
1998年 | 18篇 |
1997年 | 16篇 |
1996年 | 22篇 |
1995年 | 21篇 |
1994年 | 16篇 |
1993年 | 10篇 |
1992年 | 13篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 13篇 |
1988年 | 6篇 |
1987年 | 14篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有1041条查询结果,搜索用时 62 毫秒
991.
Peter H. Kahn Jr. Batya Friedman Brian Gill Jennifer Hagman Rachel L. Severson Nathan G. Freier Erika N. Feldman Sybil Carrre Anna Stolyar 《Journal of environmental psychology》2008,28(2):192-199
Humans will continue to adapt to an increasingly technological world. But are there costs to such adaptations in terms of human well being? Toward broaching this question, we investigated physiological effects of experiencing a HDTV quality real-time view of nature through a plasma display “window.” In an office setting, 90 participants (30 per group) were exposed either to (a) a glass window that afforded a view of a nature scene, (b) a plasma window that afforded a real-time HDTV view of essentially the same scene, or (c) a blank wall. Results showed that in terms of heart rate recovery from low-level stress the glass window was more restorative than a blank wall; in turn, a plasma window was no more restorative than a blank wall. Moreover, when participants spent more time looking at the glass window, their heart rate tended to decrease more rapidly; that was not the case with the plasma window. Discussion focuses on how the purported benefits of viewing nature may be attenuated by a digital medium. 相似文献
992.
993.
Massively parallel sequencing has revolutionized our understanding of Mendelian disorders, and many novel genes have been discovered to cause disease phenotypes when mutant. At the same time, next-generation sequencing approaches have enabled non-invasive prenatal testing of free fetal DNA in maternal blood. However, little attention has been paid to using whole exome and genome sequencing strategies for gene identification in fetal disorders that are lethal in utero, because they can appear to be sporadic and Mendelian inheritance may be missed. We present challenges and advantages of applying next-generation sequencing approaches to gene discovery in fetal malformation phenotypes and review recent successful discovery approaches. We discuss the implication and significance of recessive inheritance and cross-species phenotyping in fetal lethal conditions. Whole exome sequencing can be used in individual families with undiagnosed lethal congenital anomaly syndromes to discover causal mutations, provided that prior to data analysis, the fetal phenotype can be correlated to a particular developmental pathway in embryogenesis. Cross-species phenotyping allows providing further evidence for causality of discovered variants in genes involved in those extremely rare phenotypes and will increase our knowledge about normal and abnormal human developmental processes. Ultimately, families will benefit from the option of early prenatal diagnosis. © 2014 John Wiley & Sons, Ltd. 相似文献
994.
995.
996.
997.
Using bomb radiocarbon to estimate age and growth of the white shark,Carcharodon carcharias,from the southwestern Indian Ocean 总被引:1,自引:0,他引:1
998.
999.
Monitoring responses by birds to restoration of riparian vegetation is relatively cost-effective, but in most assessments species-specific abundances, not demography, are monitored. Data on birds collected during the nonbreeding season are particularly lacking. We captured birds in mist nets and resighted banded birds to estimate species richness and diversity, abundance, demographic indexes, and site-level persistence of permanent-resident and overwintering migrants in remnant and restored riparian sites in California. Species richness in riparian remnants was significantly higher than in restored sites because abundances of uncommon permanent residents were greater in remnants. Species richness of overwintering migrants did not differ between remnants and restored sites. Responses among overwintering migrants (but not permanent residents) to remnant and restored riparian sites differed. Capture rates were higher in remnant or restored riparian sites for 7 of 10 overwintering migratory species. For Lincoln's Sparrows (Melospiza lincolnii) and White-crowned Sparrows (Zonotrichia leucophrys) proportions of older birds were significantly higher in remnants, even though capture rates of these species were higher in restored sites. Overwinter persistence of 4 migrant species was significantly higher in remnant than in restored sites. A higher proportion of Hermit Thrushes (Catharus guttatus, 56.3%), older Fox Sparrows (Passerella iliaca, 57.1%), Lincoln's Sparrows (59.7%), and White-crowned Sparrows (67.8%) persisted in remnants than restored sites. Our results suggest restored riparian sites provide habitat for a wide variety of species in comparable abundances and diversity as occurs in remnant riparian sites. Our demographic and persistence data showed that remnants supported some species and age classes to a greater extent than restored sites. 相似文献
1000.
The natural flow regimes of rivers worldwide have been heavily altered through anthropogenic activities, and dams in particular have a pervasive effect on riverine ecosystems. Flow-regulation effects of dams negatively affect species diversity and abundance of a variety of aquatic animals, including invertebrates and fishes. However, the effects on semiaquatic animals are relatively unknown. We conducted anuran calling surveys at 42 study locations along the Broad and Pacolet Rivers in South Carolina to address the potential effects of flow regulation by damming on anuran occupancy and abundance. We estimated occupancy and abundance with Program PRESENCE. Models incorporated distance upstream and downstream from the nearest dam as covariates and urbanization pressure as an alternative stressor. Distance from dam was associated with occupancy of 2 of the 9 anuran species in our analyses and with abundance of 6 species. In all cases, distance downstream from nearest dam was a better predictor of occupancy and abundance than distance upstream from nearest dam. For all but one species, distance downstream from nearest dam was positively correlated with both occupancy and abundance. Reduced occupancy and abundance of anurans likely resulted from downstream alterations in flow regime associated with damming, which can lead to reduced area of riparian wetlands that serve as anuran breeding habitat. Our results showed that damming has a strong negative effect on multiple anuran species across large spatial extents and suggest that flow regulation can affect semiaquatic animals occupying riparian zones. 相似文献