全文获取类型
收费全文 | 387篇 |
免费 | 6篇 |
国内免费 | 4篇 |
专业分类
安全科学 | 6篇 |
废物处理 | 15篇 |
环保管理 | 29篇 |
综合类 | 89篇 |
基础理论 | 102篇 |
环境理论 | 1篇 |
污染及防治 | 111篇 |
评价与监测 | 27篇 |
社会与环境 | 15篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 4篇 |
2022年 | 10篇 |
2021年 | 9篇 |
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 21篇 |
2015年 | 12篇 |
2014年 | 20篇 |
2013年 | 33篇 |
2012年 | 21篇 |
2011年 | 30篇 |
2010年 | 18篇 |
2009年 | 23篇 |
2008年 | 19篇 |
2007年 | 12篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 9篇 |
2002年 | 4篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1991年 | 3篇 |
1985年 | 2篇 |
1981年 | 3篇 |
1978年 | 3篇 |
1974年 | 3篇 |
1968年 | 2篇 |
1965年 | 3篇 |
1963年 | 2篇 |
1962年 | 2篇 |
1961年 | 2篇 |
1958年 | 4篇 |
1957年 | 4篇 |
1956年 | 3篇 |
1955年 | 4篇 |
1948年 | 1篇 |
1943年 | 3篇 |
1941年 | 1篇 |
1933年 | 1篇 |
1932年 | 1篇 |
1914年 | 1篇 |
排序方式: 共有397条查询结果,搜索用时 15 毫秒
101.
Threats to Imperiled Freshwater Fauna 总被引:10,自引:0,他引:10
Brian D. Richter David P. Braun Michael A. Mendelson & Lawrence L. Master 《Conservation biology》1997,11(5):1081-1093
Threats to imperiled freshwater fauna in the U.S. were assessed through an experts survey addressing anthropogenic stressors and their sources. Specifically, causes of historic declines and current limits to recovery were identified for 135 imperiled freshwater species of fishes, crayfishes, dragonflies and damselflies, mussels, and amphibians. The survey was designed to identify threats with sufficient specificity to inform resource managers and regulators faced with translating information about predominant biological threats into specific, responsive actions. The findings point to altered sediment loads and nutrient inputs from agricultural nonpoint pollution; interference from exotic species; and altered hydrologic regimes associated with impoundment operations as the three leading threats nationwide, accompanied by many lesser but still significant threats. Variations in threats among regions and among taxa were also evident. Eastern species are most commonly affected by altered sediment loads from agricultural activities, whereas exotic species, habitat removal/damage, and altered hydrologic regimes predominate in the West. Altered sediment loading from agricultural activities and exotic species are dominant problems for both eastern mussels and fishes. However, eastern fishes also appear to be suffering from municipal nonpoint pollution (nutrients and sediments), whereas eastern mussels appear to be more severely affected by altered nutrient impacts from hydroelectric impoundments and agricultural runoff. Our findings suggest that control of nonpoint source pollution associated with agriculture activities should be a very high priority for agricultural producers and governmental support programs. Additonally, the large number of hydropower dams in the U.S. subject to federal re-licensing in coming years suggests a significant opportunity to restore natural hydrologic regimes in the affected rivers. 相似文献
102.
103.
104.
105.
106.
107.
Aravindakshan Sreejith Krupnik Timothy J. Shahrin Sumona Tittonell Pablo Siddique Kadambot H. M. Ditzler Lenora Groot Jeroen C. J. 《Environment, Development and Sustainability》2021,23(11):16588-16616
Environment, Development and Sustainability - Appreciating and dealing with the plurality of farmers’ perceptions and their contextual knowledge and perspectives of the functioning and... 相似文献
108.
Carolina Briones Pablo Presa Montse Pérez Alfonso Pita Ricardo Guiñez 《Marine Biology》2013,160(12):3143-3156
Connectivity in benthic marine animals with complex life cycles occurs primarily during the pelagic larval stage and depends deterministically on oceanographic dynamics. The scale of such larval dispersal is highly uncertain due the difficulty of direct measurement and poor knowledge of larval dynamics and ocean flow variability. This study characterizes the pattern of genetic connectivity in the ecosystem engineer Perumytilus purpuratus between latitudes 23°S and 33°S, which includes the ecological discontinuity reported for many taxa north to 32°S at the southeast Pacific. The genetic discontinuity observed in P. purpuratus around 26°S is described herein while that detected at 28°S is in line with the ecological discontinuity (in coverage, recruitment and density) previously reported for this mussel between 28°S and 32°S. Both discontinuities delimitate two major gene pools upon Bayesian inferences on geographical variation of five microsatellite loci. Interestingly, marker Pepu1 was responsible for most variation between pools and was potentially under selection. In fact, inferences excluding Pepu1 produced a single gene pool (k = 1) in central-northern Chile. The IBD connectivity pattern observed among P. purpuratus beds distributed in the interval 23°S–33°S is congruent with processes driven by larval dynamics, and the dominant equatorward Humboldt Current along a coast largely unaffected by ice during the last Pleistocene glaciation. However, the selective scenario unveiled by microsatellite Pepu1 inside the 25°S–28°S ecological discontinuity is consistent with selective processes associated with specific mesoscale properties operating in this area. This study highlights the usefulness of integrating different oceanographic scales, ecological data and population genetics to better understand connectivity of benthic marine species. 相似文献
109.
C. Jantzen V. Häussermann G. Försterra J. Laudien M. Ardelan S. Maier C. Richter 《Marine Biology》2013,160(10):2597-2607
Increasing dissolution of anthropogenic-released carbon dioxide into the world’s oceans is causing ocean acidification (OA). OA is thought to negatively affect most marine-calcifying organisms, notably cold-water corals (CWC), which may be especially sensitive due to the deep and cold waters they normally thrive in. However, the impact of OA on CWC is difficult to predict. Recorded distributions of CWC are rarely linked to in situ water chemistry, and the boundaries of their distributions are not clearly defined. The fjord Comau in Chilean Patagonia features pronounced pH gradients, and up to 0.5 pH units have been recorded both vertically (at some sites within 50 m depth) and less distinct horizontally (from head to mouth). The cosmopolite coral Desmophyllum dianthus grows along the course of the fjord and of the entire pH range. It occurs in shallow depths (below 12 m, pH 8.1) as part of a deep-water emergence community, but also in 225 m depth at a pH of 7.4. Based on pH and total alkalinity, data calculations of the associated carbonate chemistry revealed that this CWC thrives commonly close the aragonite (the orthogonal crystal form of calcium carbonate, the mineral structure of coral skeletons) saturation horizon and even below. This suggests a high adaptation potential of D. dianthus to adjust its calcification performance to conditions thermodynamically unfavourable for the precipitation of aragonite. 相似文献
110.