全文获取类型
收费全文 | 755篇 |
免费 | 13篇 |
国内免费 | 6篇 |
专业分类
安全科学 | 43篇 |
废物处理 | 35篇 |
环保管理 | 242篇 |
综合类 | 53篇 |
基础理论 | 165篇 |
污染及防治 | 138篇 |
评价与监测 | 61篇 |
社会与环境 | 30篇 |
灾害及防治 | 7篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 15篇 |
2017年 | 15篇 |
2016年 | 15篇 |
2015年 | 19篇 |
2014年 | 15篇 |
2013年 | 53篇 |
2012年 | 20篇 |
2011年 | 35篇 |
2010年 | 25篇 |
2009年 | 26篇 |
2008年 | 50篇 |
2007年 | 29篇 |
2006年 | 43篇 |
2005年 | 36篇 |
2004年 | 32篇 |
2003年 | 31篇 |
2002年 | 19篇 |
2001年 | 21篇 |
2000年 | 23篇 |
1999年 | 12篇 |
1998年 | 7篇 |
1997年 | 12篇 |
1996年 | 10篇 |
1995年 | 11篇 |
1994年 | 14篇 |
1993年 | 14篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 10篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1980年 | 7篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1972年 | 3篇 |
1971年 | 5篇 |
排序方式: 共有774条查询结果,搜索用时 187 毫秒
671.
Beyond Biology: toward a More Public Ecology for Conservation 总被引:3,自引:0,他引:3
Abstract: The ultimate purpose of conservation science is to inform and affect conservation policy. Therefore, conservation biologists and all the people who produce, review, and apply conservation research should evaluate the success of their knowledge according to its ability to influence conservation decisions. In addition to possessing conventional "scientific" attributes such as validity, generalizability, and precision, conservation knowledge must also possess qualities that make it effective in the political arena of decision making. "Public ecology" is a philosophy and practice of conservation science that goes beyond biology and beyond the norms of modern science to construct knowledge that is useful for environmental decision making. As post-normal conservation science, public ecology is defined by the following six attributes: evaluative, contextual, multiscalar, integrative, adaptive, and accessible. We discuss the need for a more public ecology and describe the qualites that make it a more powerful ecology. 相似文献
672.
Bruce E. Young †††† Karen R. Lips † Jamie K. Reaser ‡ Roberto Ibáñez § Antonio W. Salas J. Rogelio Cedeño †† Luis A. Coloma ‡‡ Santiago Ron ‡‡ Enrique La Marca §§ John R. Meyer Antonio Muñoz ††† Federico Bolaños ‡‡‡ Gerardo Chaves ‡‡‡ David Romo§§§ 《Conservation biology》2001,15(5):1213-1223
Abstract: Although dramatic amphibian population declines have been reported worldwide, our understanding of the extent of the declines in Latin America, where amphibian diversity is high, is limited to a few well-documented studies. To better understand the geographic extent of declines, their possible causes, and the measures needed to improve Latin American scientists' ability to research the phenomenon and make effective management recommendations, we convened three regional workshops with 88 Latin American herpetologists and conservationists. Population declines are widespread in Latin America. At least 13 countries have experienced declines, and in 40 cases species are now thought to be extinct or extirpated in a country where they once occurred. Declines or extinctions have affected 30 genera and nine families of amphibians. Most declines have occurred in remote highlands, above 500 m in elevation in Central America and above 1000 m in the Andes. Most documented declines occurred in the 1980s. Of the possible causes studied to date, climate change appears to be important at one site and chytrid fungal disease has been identified at sites in three countries. Although many monitoring studies are currently underway in a variety of habitats, most studies are recent and of short duration. In a signed resolution, workshop participants called for greater collaboration and communication among scientists working in Latin America to understand the geographic extent of population declines and the distribution of possible causal factors. In situ conservation is important to protect habitats, but captive-rearing programs for species subject to imminent extinction are also needed. Better understanding of the taxonomy and natural history of amphibians and more funding for research and monitoring are critical to developing a scientific basis for management action to arrest and reverse population declines. 相似文献
673.
674.
Modeling Phosphate Influence on Arsenate Reduction Kinetics by a Freshwater Cyanobacterium 总被引:1,自引:0,他引:1
Arsenic speciation in natural surface-water systems can be highly impacted through biological processes that result in non-thermodynamically
predicted species to dominate the system. In laboratory experiments, arsenate reduction by a freshwater cyanobacterium exhibited
saturation kinetics increasingly inhibited by elevating solution phosphate concentrations. Approximately 100% arsenate reduction
occurred by days 4, 7, and 10 in the low (0.35 μm), middle (3.5 μm), and high (35 μm) phosphate treatments, respectively,
with maximum arsenate reduction rates ranged from 0.013 μmol As g C−1 day−1 in the high-phosphate treatment to 0.398 μmol As g C−1 day−1 in the low-phosphate treatment. Saturation kinetic models were utilized to evaluate the impact of cell growth and arsenate-phosphate
uptake competition on arsenate reduction rates by the cyanobacterium. Results showed reduced arsenicals dominate arsenic speciation
once growth reached steady state, indicating reduced arsenicals may dominate natural systems, even when considering conservatively
high, abiotic arsenic reoxidation. 相似文献
675.
676.
Solid-phase microextraction (SPME) was evaluated for the detection and quantification of the gas-phase carbonyls: citronellal, glyoxal, methylglyoxal, and beta-ionone. Prepared air samples containing the carbonyl compounds were collected at a flow rate of 2.8 L min(-1) in an impinger containing a 25% reagent water/75% methanol collection liquid. The aqueous samples were then derivatized with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA), extracted with a PDMS/DVB coated SPME fiber, and analyzed by GC-MS. Detection limits with a sample air volume of 76 L were calculated to be 0.03 ppbv, 0.34 ppbv, 0.12 ppbv, and 0.28 ppbv for citronellal, glyoxal, methylglyoxal, and beta-ionone, respectively. 相似文献
677.
La Daana K. Kanhai Judith F. Gobin Denise M. Beckles Bruce Lauckner Azad Mohammed 《Environmental monitoring and assessment》2014,186(3):1961-1976
Metals can have significant impacts on inhabitants of mangrove swamps as well as consumers of mangrove-associated fauna. Yet, for several Caribbean islands, assessments regarding the impact of metals on such ecosystems are particularly sparse. The present study investigated the distribution and potential impact of Cd, Cr, Cu, Ni, Pb and Zn in the Caroni Swamp, Trinidad and Tobago’s largest mangrove ecosystem. Surface sediments and mangrove oysters (Crassostrea rhizophorae) from 10 sites in the swamp were analysed for the 6 identified metals. The concentration ranges (in μg/g dry wt.) of metals in sediments from Caroni Swamp were: Zn (113.4–264.6), Cr (27–69.7), Ni (10.7–41.1) and Cu (11–40.7). Based on Canadian Sediment Quality Guidelines (CSQGs), metals in sediments posed a low to medium risk to aquatic life. The concentration ranges (in μg/g wet wt.) for metals in Crassostrea rhizophorae tissues were: Zn (123.2–660), Cu (4.2–12.3), Ni (0.1–5.5), Pb (0.1–0.9), Cr (0.2–0.3) and Cd (0.1–0.2). Multiple evaluations indicated that zinc posed a potential threat to the health of oyster consumers. Information from this study is vital for managing the Caroni Swamp, safeguarding the health of consumers of shellfish on this Caribbean island and serving as a useful baseline for future local and regional risk assessments. 相似文献
678.
Thorsten Stahl Sandy Falk Alice Rohrbeck Sebastian Georgii Christin Herzog Alexander Wiegand Svenja Hotz Bruce Boschek Holger Zorn Hubertus Brunn 《Environmental Sciences Europe》2017,29(1):18
Background
Drinking bottles and stove-top moka pots made of aluminum have become very popular. Storing drinks in bottles and preparing coffee in a moka pot may result in the migration of aluminum to the beverage.Results/Conclusions
In a systematic study of aluminum drinking bottles, it has been shown that drinking a mixture of apple juice and mineral water in an aluminum bottle may reach 86.6% of the total weekly intake (TWI) for adults, and drinking tea from an aluminum bottle may exceed the TWI (145%) for a child weighing 15 kg. In contrast, preparing coffee in an aluminum moka pot results in a maximum of 4% to TWI, if an average of 3.17 L coffee is consumed per week, even if the pots are washed in the dishwasher, against the explicit instructions of the manufacturer.679.
Thorsten Stahl Sandy Falk Alice Rohrbeck Sebastian Georgii Christin Herzog Alexander Wiegand Svenja Hotz Bruce Boschek Holger Zorn Hubertus Brunn 《Environmental Sciences Europe》2017,29(1):19
Background
In spite of the prevalence of aluminum in nature, no organism has been found to date which requires this element for its biological functions. The possible health risks to human beings resulting from uptake of aluminum include detrimental effects to the hemopoietic system, the nervous system and bones. Aluminum is used in many fields and occurs in numerous foodstuffs. Food contact materials containing aluminum represent an anthropogenic source of dietary aluminum.Results
As a result of their frequent use in private households a study was undertaken to detect migration of this metal to foodstuffs from drink containers, coffee pots, grill pans, and camping cookware made of aluminum.Conclusions
An estimate of the health risk to consumers is calculated, based on the tolerable weekly intake (TWI) specified by the European Food Safety Authority of 1 mg/kg body weight for all groups of people. In some instances the TWI is significantly exceeded, dependent upon the food contact material and the food itself.680.
Modeling the Effects of Tile Drain Placement on the Hydrologic Function of Farmed Prairie Wetlands
下载免费PDF全文
![点击此处可从《Journal of the American Water Resources Association》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Brett Werner John Tracy W. Carter Johnson Richard A. Voldseth Glenn R. Guntenspergen Bruce Millett 《Journal of the American Water Resources Association》2016,52(6):1482-1492
The early 2000s saw large increases in agricultural tile drainage in the eastern Dakotas of North America. Agricultural practices that drain wetlands directly are sometimes limited by wetland protection programs. Little is known about the impacts of tile drainage beyond the delineated boundaries of wetlands in upland catchments that may be in agricultural production. A series of experiments were conducted using the well‐published model WETLANDSCAPE that revealed the potential for wetlands to have significantly shortened surface water inundation periods and lower mean depths when tile is placed in certain locations beyond the wetland boundary. Under the soil conditions found in agricultural areas of South Dakota in North America, wetland hydroperiod was found to be more sensitive to the depth that drain tile is installed relative to the bottom of the wetland basin than to distance‐based setbacks. Because tile drainage can change the hydrologic conditions of wetlands, even when deployed in upland catchments, tile drainage plans should be evaluated more closely for the potential impacts they might have on the ecological services that these wetlands currently provide. Future research should investigate further how drainage impacts are affected by climate variability and change. 相似文献