全文获取类型
收费全文 | 765篇 |
免费 | 16篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 53篇 |
废物处理 | 22篇 |
环保管理 | 116篇 |
综合类 | 231篇 |
基础理论 | 152篇 |
环境理论 | 3篇 |
污染及防治 | 127篇 |
评价与监测 | 35篇 |
社会与环境 | 26篇 |
灾害及防治 | 17篇 |
出版年
2023年 | 12篇 |
2021年 | 11篇 |
2020年 | 21篇 |
2019年 | 8篇 |
2018年 | 23篇 |
2017年 | 13篇 |
2016年 | 26篇 |
2015年 | 28篇 |
2014年 | 15篇 |
2013年 | 38篇 |
2012年 | 47篇 |
2011年 | 52篇 |
2010年 | 29篇 |
2009年 | 39篇 |
2008年 | 38篇 |
2007年 | 36篇 |
2006年 | 37篇 |
2005年 | 18篇 |
2004年 | 13篇 |
2003年 | 18篇 |
2002年 | 22篇 |
2001年 | 12篇 |
2000年 | 9篇 |
1999年 | 14篇 |
1998年 | 9篇 |
1997年 | 11篇 |
1995年 | 7篇 |
1994年 | 12篇 |
1992年 | 6篇 |
1991年 | 10篇 |
1989年 | 5篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1974年 | 5篇 |
1971年 | 4篇 |
1967年 | 6篇 |
1965年 | 4篇 |
1964年 | 4篇 |
1961年 | 7篇 |
1960年 | 4篇 |
1957年 | 4篇 |
1956年 | 4篇 |
1948年 | 4篇 |
1940年 | 3篇 |
1937年 | 3篇 |
1928年 | 3篇 |
1920年 | 5篇 |
1916年 | 3篇 |
1913年 | 3篇 |
排序方式: 共有782条查询结果,搜索用时 343 毫秒
391.
Lisa M. Kurian Laura K. Lautz Myron J. Mitchell 《Journal of the American Water Resources Association》2013,49(2):264-283
Abstract: More than 85% of NO3? losses from watersheds in the northeastern United States are exported during winter months (October 1 to May 30). Interannual variability in NO3? loads to individual streams is closely related to interannual climatic variations, particularly during the winter. The objective of our study was to understand how climatic and hydrogeological factors influence NO3? dynamics in small watersheds during the winter. Physical parameters including snow depth, soil temperature, stream discharge, and water table elevation were monitored during the 2007‐2008 winter in two small catchments in the Adirondack Mountains, New York State. Snowpack persisted from mid‐December to mid‐April, insulating soils such that only two isolated instances of soil frost were observed during the study period. NO3? export during a mid‐winter rain‐on‐snowmelt event comprised between 8 and 16% of the total stream NO3? load for the four‐month winter study period. This can be compared with the NO3? exported during the final spring melt, which comprised between 38 and 45% of the total four‐month winter NO3? load. Our findings indicate that minor melt events were detectable with changes in soil temperature, streamflow, groundwater level, and snow depth. But, based on loading, these events were relatively minor contributors to winter NO3? loss. A warmer climate and fluctuating snowpack may result in more major mid‐winter melt events and greater NO3? export to surface waters. 相似文献
392.
John Eyles Kathi Wilson Lisa Mu Sue Keller-Olaman Susan Elliott 《Local Environment》2013,18(10):981-998
This study examines lay perceptions of the environment and its perceived relation to health at three scales: the environment at large, the neighbourhood, and the home. Interviews were conducted with residents from two contrasting neighbourhoods in the industrial city of Hamilton, Canada. The results reveal variations in perceptions of the environment–health link between residents in the two study neighbourhoods as well as across the different scales. Air pollution and proximity to industry were frequently implicated in lay understandings of the general and neighbourhood environments. In contrast, the home environment was seen as relatively insulated and safe. Furthermore, personal control mechanisms (e.g. cleanliness) were believed to mitigate adverse health impacts in the home and yard while the general environment was seen to be outside of such control. The significance of the findings is discussed in terms of future research and policy relevance. 相似文献
393.
Invasive cordgrass modifies wetland trophic function 总被引:18,自引:0,他引:18
Vascular plants strongly control belowground environments in most ecosystems. Invasion by vascular plants in coastal wetlands, and by cordgrasses (Spartina spp.) in particular, are increasing in incidence globally, with dramatic ecosystem-level consequences. We examined the trophic consequences of invasion by a Spartina hybrid (S. alterniflora x S. foliosa) in San Francisco Bay (USA) by documenting differences in biomass and trophic structure of benthic communities between sediments invaded by Spartina and uninvaded sediments. We found the invaded system shifted from an algae-based to a detritus-based food web. We then tested for a relationship between diet and tolerance to invasion, hypothesizing that species that consume Spartina detritus are more likely to inhabit invaded sediments than those that consume surface algae. Infaunal diets were initially examined with natural abundance stable isotope analyses and application of mixing models, but these yielded an ambiguous picture of food sources. Therefore, we conducted isotopic enrichment experiments by providing 15N-labeled Spartina detritus both on and below the sediment surface in areas that either contained Spartina or were unvegetated. Capitellid and nereid polychaetes, and oligochaetes, groups shown to persist following Spartina invasion of San Francisco Bay tidal flats, took up 15N from labeled native and invasive Spartina detritus. In contrast, we found that amphipods, bivalves, and other taxa less tolerant to invasion consumed primarily surficial algae, based on 13C enrichment experiments. Habitat (Spartina vs. unvegetated patches) and location of detritus (on or within sediments) did not affect 15N uptake from detritus. Our investigations support a "trophic shift" model for ecosystem response to wetland plant invasion and preview loss of key trophic support for fishes and migratory birds by shifting dominance to species not widely consumed by species at higher trophic levels. 相似文献
394.
395.
Skeletochronological analysis of Kemp’s ridley (Lepidochelys kempii) and loggerhead (Caretta caretta) sea turtle humeri and scleral ossicles was conducted to (1) describe the characteristics of scleral ossicles in these species,
(2) determine whether the scleral ossicles contain annually deposited skeletal growth marks and (3) evaluate the potential
for skeletochronological analysis of ossicles to obtain age data for size classes and species of sea turtles whose humeri
exhibit prohibitive amounts of growth mark resorption. Humeri, entire eyes, and/or individual scleral ossicles were collected
from stranded, dead sea turtles that were found along the coasts of Florida, North Carolina, Virginia, and Texas, USA. Samples
were taken from a total of 77 neritic, juvenile Kemp’s ridleys ranging from 21.1 to 56.8 cm straightline carapace length (SCL),
as well as two Kemp’s ridley hatchlings. For loggerheads, samples were obtained from 65 neritic juvenile and adult turtles
ranging from 44.7 to 103.6 cm SCL and ten hatchlings. Examination of the ossicles revealed the presence of marks similar in
appearance to those found in humeri. The number of marks in the ossicles and humeri of individual juvenile Kemp’s ridleys
for which both structures were collected (n = 55) was equivalent, strongly indicating that the marks are annual. However, in large juvenile and adult loggerhead turtles
(n = 65), some significant resorption of early growth marks was observed, suggesting that although ossicles might be useful
for skeletochronological analysis of small juveniles, they may not provide a reasonable alternative to humeri for obtaining
age estimates for older loggerhead sea turtles. 相似文献
396.
Amphibian Breeding and Climate Change 总被引:5,自引:0,他引:5
397.
398.
399.
400.
Sebastian Busse Dominik Lutter Gerhard Heldmaier Martin Jastroch Carola W. Meyer 《Die Naturwissenschaften》2014,101(11):1003-1006
The grey short-tailed opossum, Monodelphis domestica, has been an established research animal for more than five decades, but relatively, little is known about its thermophysiology. Here we studied core body temperature (T b) and metabolic rate (MR) of female adult M. domestica housed in the laboratory at an ambient temperature (T a) of 26 °C. In expanding previous reports, the average recorded core T b of M. domestica was 34.3 °C. The T b of an individual M. domestica can drop below 30 °C (minimal T b: 28.6 °C) accompanied by a reduction in MR of up to 52 % even while having ad libitum access to food. These findings demonstrate for the first time the presence of spontaneous torpor in M. domestica. Metabolic suppression at relatively high T a and T b furthermore broadens our perspective on the use of torpor as a metabolic strategy not just restricted to cold climates. 相似文献