全文获取类型
收费全文 | 1206篇 |
免费 | 20篇 |
国内免费 | 11篇 |
专业分类
安全科学 | 69篇 |
废物处理 | 75篇 |
环保管理 | 292篇 |
综合类 | 126篇 |
基础理论 | 221篇 |
环境理论 | 2篇 |
污染及防治 | 298篇 |
评价与监测 | 98篇 |
社会与环境 | 39篇 |
灾害及防治 | 17篇 |
出版年
2023年 | 9篇 |
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 16篇 |
2019年 | 16篇 |
2018年 | 20篇 |
2017年 | 18篇 |
2016年 | 22篇 |
2015年 | 20篇 |
2014年 | 26篇 |
2013年 | 134篇 |
2012年 | 40篇 |
2011年 | 56篇 |
2010年 | 53篇 |
2009年 | 52篇 |
2008年 | 59篇 |
2007年 | 66篇 |
2006年 | 68篇 |
2005年 | 48篇 |
2004年 | 33篇 |
2003年 | 53篇 |
2002年 | 46篇 |
2001年 | 19篇 |
2000年 | 14篇 |
1999年 | 19篇 |
1998年 | 21篇 |
1997年 | 10篇 |
1996年 | 11篇 |
1995年 | 23篇 |
1994年 | 12篇 |
1993年 | 10篇 |
1992年 | 15篇 |
1991年 | 13篇 |
1990年 | 17篇 |
1989年 | 13篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 15篇 |
1984年 | 11篇 |
1983年 | 14篇 |
1982年 | 19篇 |
1981年 | 24篇 |
1980年 | 10篇 |
1979年 | 13篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 8篇 |
1972年 | 4篇 |
1971年 | 4篇 |
排序方式: 共有1237条查询结果,搜索用时 492 毫秒
331.
Julie A. Robinson †† Kamlesh P. Lulla Minoru Kashiwagi † Maggie Suzuki † M. Duane Nellis ‡ Charles E. Bussing § Warren J. Lee Long Len J. McKenzie 《Conservation biology》2001,15(4):876-884
Abstract: National Aeronautics and Space Administration ( NASA) photographs taken by astronauts from low Earth orbit can provide information relevant to conservation biology. This data source is now more accessible because of improvements in digitizing technology, Internet file transfer, and availability of image processing software. We present three examples of conservation-related projects that benefited from the use of astronaut photographs. First, NASA scientists requested that astronauts photograph the area of the controversial Isahaya Bay reclamation project in Japan. Japanese researchers used photographs from before and after the reclamation as a tool for communication with the public about the effects of tidal-flat loss. The newly acquired images and the availability of high-resolution digital images from NASA archives provided timely public information on the observed changes. Second, we digitally classified and analyzed a Space Shuttle photograph of Chobe National Park in Botswana to identify the locations of woodlands affected by elephants. Field validation later confirmed that areas identified on the image showed evidence of elephant damage. Third, we used a summary map from intensive field surveys of seagrasses in Shoalwater Bay, Australia, as reference data for a supervised classification of a digitized photograph taken from orbit. The classification distinguished seagrasses, sediments, and mangroves with accuracy approximating that in studies using other satellite remote-sensing data. Astronaut photographs are in the public domain, and the database of nearly 400,000 photographs from the late 1960s to the present is available at a single searchable location on the Internet ( http://eol.jsc.nasa.gov/sseop ). These photographs can be used by conservation biologists as a source of general information about the landscape and for quantitative mapping. 相似文献
332.
This paper uses a dynamic model with asymmetric players to explore the question: In a second-best world, should environmental regulations for transboundary pollutants be carried out locally or centrally? We find that combined payoffs are larger with decentralized control if payoffs are sufficiently heterogeneous and initial pollution stocks are sufficiently small. This result is obtained because the central authority applies one shadow price to pollution (i.e., it uses uniform standards), whereas local authorities use different shadow prices, and therefore different standards. 相似文献
333.
Lirman D Gracias NR Gintert BE Gleason AC Reid RP Negahdaripour S Kramer P 《Environmental monitoring and assessment》2007,125(1-3):59-73
The recent decline in the condition of coral reef communities worldwide has fueled the need to develop innovative assessment
tools to document coral abundance and distribution rapidly and effectively. While most monitoring programs rely primarily
on data collected in situ by trained divers, digital photographs and video are used increasingly to extract ecological indicators, provide a permanent
visual record of reef condition, and reduce the time that divers spend underwater. In this study, we describe the development
and application of a video-based reef survey methodology based on an algorithm for image registration and the estimation of
image motion and camera trajectory. This technology was used to construct two-dimensional, spatially accurate, high-resolution
mosaics of the reef benthos at a scale of up to 400 m2. The mosaics were analyzed to estimate the size and percent cover of reef organisms and these ecological indicators of reef
condition were compared to similar measurements collected by divers to evaluate the potential of the mosaics as monitoring
tools. The ecological indicators collected by trained divers compared favorably with those measured directly from the video
mosaics. Five out of the eight categories chosen (hard corals, octocorals, Palythoa, algal turf, and sand) showed no significant differences in percent cover based on survey method. Moreover, no significant
differences based on survey method were found in the size of coral colonies. Lastly, the capability to extract the same reef
location from mosaics collected at different times proved to be an important tool for documenting change in coral abundance
as the removal of even small colonies (<10 cm in diameter) was easily documented. The two-dimensional video mosaics constructed
in this study can provide repeatable, accurate measurements on the reef-plot scale that can complement measurements on the
colony-scale made by divers and surveys conducted at regional scales using remote sensing tools. 相似文献
334.
Uranium removal from groundwater via in situ biostimulation: Field-scale modeling of transport and biological processes 总被引:1,自引:0,他引:1
Yabusaki SB Fang Y Long PE Resch CT Peacock AD Komlos J Jaffe PR Morrison SJ Dayvault RD White DC Anderson RT 《Journal of contaminant hydrology》2007,93(1-4):216-235
During 2002 and 2003, bioremediation experiments in the unconfined aquifer of the Old Rifle UMTRA field site in western Colorado provided evidence for the immobilization of hexavalent uranium in groundwater by iron-reducing Geobacter sp. stimulated by acetate amendment. As the bioavailable Fe(III) terminal electron acceptor was depleted in the zone just downgradient of the acetate injection gallery, sulfate-reducing organisms came to dominate the microbial community. In the present study, we use multicomponent reactive transport modeling to analyze data from the 2002 field experiment to identify the dominant transport and biological processes controlling uranium mobility during biostimulation, and determine field-scale parameters for these modeled processes. The coupled process simulation approach was able to establish a quantitative characterization of the principal flow, transport, and reaction processes based on the 2002 field experiment, that could be applied without modification to describe the 2003 field experiment. Insights gained from this analysis include field-scale estimates of the bioavailable Fe(III) mineral threshold for the onset of sulfate reduction, and rates for the Fe(III), U(VI), and sulfate terminal electron accepting processes. 相似文献
335.
Coupled human and natural systems 总被引:18,自引:0,他引:18
Liu J Dietz T Carpenter SR Folke C Alberti M Redman CL Schneider SH Ostrom E Pell AN Lubchenco J Taylor WW Ouyang Z Deadman P Kratz T Provencher W 《Ambio》2007,36(8):639-649
Humans have continuously interacted with natural systems, resulting in the formation and development of coupled human and natural systems (CHANS). Recent studies reveal the complexity of organizational, spatial, and temporal couplings of CHANS. These couplings have evolved from direct to more indirect interactions, from adjacent to more distant linkages, from local to global scales, and from simple to complex patterns and processes. Untangling complexities, such as reciprocal effects and emergent properties, can lead to novel scientific discoveries and is essential to developing effective policies for ecological and socioeconomic sustainability. Opportunities for truly integrating various disciplines are emerging to address fundamental questions about CHANS and meet society's unprecedented challenges. 相似文献
336.
Progress in developing theories of interpersonal influence depends on the identification of meaningful and measurable constructs for classifying influence behavior. We assessed the construct validity and relative effectiveness of two new influence tactics with a field survey study, an incident study, and a laboratory experiment. The confirmatory factor analysis of data from the survey study indicated that collaboration and apprising were distinct from nine proactive tactics identified in earlier research. Additional evidence for construct validity was provided by a comparison of tactics in terms of expected differences in influence outcomes, frequency of use, and differential use with subordinates and peers. Managers who understand the differences among the tactics will be more effective in influencing people in organizations. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
337.
Dana M. Bethea Loraine Hale John K. Carlson Enric Cortés Charles A. Manire James Gelsleichter 《Marine Biology》2007,152(5):1009-1020
To examine variation in diet and daily ration of the bonnethead shark, Sphyrna tiburo (Linnaeus 1758), animals were collected from three areas in the eastern Gulf of Mexico: northwest Florida (∼29°40′N, 85°13′W),
Tampa Bay near Anclote Key (∼28°10′N, 82°42.5′W), and Florida Bay (∼24°50′N, 80°48′W) from March through September, 1998–2000.
In each area, diet was assessed by life stage (young-of-the year, juveniles, and adults) and quantified using five indices:
percent by number (%N), percent by weight (%W), frequency of occurrence (%O), index of relative importance expressed on a
percent basis (%IRI), and %IRI based on diet category (%IRIDC). Diet could not be assessed for young-of-the-year in Tampa Bay or Florida Bay owing to low sample size. Diet analysis showed
an ontogenetic shift in northwest Florida. Young-of-the-year stomachs from northwest Florida (n = 68, 1 empty) contained a mix of seagrass and crustaceans while juvenile stomachs (n = 82, 0 empty) contained a mix of crabs and seagrass and adult stomachs (n = 39, 1 empty) contained almost exclusively crabs. Crabs made up the majority of both juvenile and adult diet in Tampa Bay
(n = 79, 2 empty, and n = 88, 1 empty, respectively). Juvenile stomachs from Florida Bay (n = 72, 0 empty) contained seagrass and a mix of crustaceans while adult stomachs contained more shrimp and cephalopods (n = 82, 3 empty). Diets in northwest Florida and Tampa Bay were similar. The diet in Florida Bay was different from those in
the other two areas, consisting of fewer crabs and more cephalopods and lobsters. Plant material was found in large quantities
in all stomachs examined from all locations (>15 %IRIDC in 6 of the 7 life stage-area combinations, >30 %IRIDC in 4 of the 7 combinations, and 62 %IRIDC in young-of-the-year diet in northwest Florida). Using species- and area-specific inputs, a bioenergetic model was constructed
to estimate daily ration. Models were constructed under two scenarios: assuming plant material was and was not part of the
diet. Overall, daily ration was significantly different by sex, life stage, and region. The bioenergetic model predicted increasing
daily ration with decreasing latitude and decreasing daily ration with ontogeny regardless of the inclusion or exclusion of
plant material. These results provide evidence that bonnetheads continuously exposed to warmer temperatures have elevated
metabolism and require additional energy consumption to maintain growth and reproduction.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
338.
When individuals investigate a sexual harassment claim that stems from a dissolved workplace romance, their responses to the claim are likely influenced by their ethical standards and legal standards. We propose a person–situation interactionist decision‐making process through which investigators' ethical standards may override legal standards when responding to social–sexual conduct at work. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
339.
Charles P. Gerba Adam Ross Kazue Takizawa Ian L. Pepper 《Food and environmental virology》2011,3(1):43-45
The ASTM Method D4994-89 has been used in the United States for almost two decades to assess the virological quality of biosolids.
However, the efficiency of this method for recovery of different enteric viruses has never been determined. The method was
found to recover several different enteroviruses and adenovirus 2 with an efficiency ranging from 18.1 ± 5.5 to 24.6 ± 7.8%. 相似文献
340.
Michael Greenberg Karen Lowrie Justin Hollander Joanna Burger Charles Powers Michael Gochfeld 《补救:环境净化治理成本、技术与工艺杂志》2008,18(3):79-90
We examined site‐specific advisory board (SSAB) minutes and local newspaper coverage of the Fernald, Hanford, Idaho, Oak Ridge, Rocky Flats, and Savannah River sites of the U.S. Department of Energy (US DOE) in order to determine the importance of risk‐related issues related to remediation and other forms of environmental management. About one‐third of SSAB issues were risk‐related, and these were disproportionately major issues at meetings. The media focused on risks associated with remediation and other forms of waste management. The analysis implies that contractors and government officials need to establish and maintain communications with advisory panels and accentuate these contacts well in advance of contemplated new actions. © 2008 Wiley Periodicals, Inc. 相似文献