全文获取类型
收费全文 | 256篇 |
免费 | 12篇 |
国内免费 | 8篇 |
专业分类
安全科学 | 10篇 |
废物处理 | 3篇 |
环保管理 | 73篇 |
综合类 | 32篇 |
基础理论 | 77篇 |
污染及防治 | 60篇 |
评价与监测 | 12篇 |
社会与环境 | 5篇 |
灾害及防治 | 4篇 |
出版年
2021年 | 2篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 9篇 |
2011年 | 10篇 |
2010年 | 11篇 |
2009年 | 9篇 |
2008年 | 14篇 |
2007年 | 12篇 |
2006年 | 8篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 18篇 |
2002年 | 8篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1971年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有276条查询结果,搜索用时 15 毫秒
161.
The role of religious factors in the disaster experience has been under‐investigated. This is despite evidence of their influence throughout the disaster cycle, including: the way in which the event is interpreted; how the community recovers; and the strategies implemented to reduce future risk. This qualitative study examined the role of faith in the disaster experience of four faith communities in the Hawaiian Islands of the United States. Twenty‐six individuals from the Bahá'í, Buddhist, Church of Jesus Christ of Latter‐day Saints (LDS), and United Methodist Church communities participated, including 10 faith leaders and 16 laypersons. The results suggest that religious narratives provide a framework for interpretation of, preparedness for, and responses to disasters. Preparedness varied widely across faith communities, with the LDS community reporting greater levels of preparedness than other communities. Recommendations include the development of collaborative efforts between disaster managers and faith leaders to increase preparedness within faith communities, which may facilitate community‐wide disaster risk reduction. 相似文献
162.
Natasha B. Kotliar Bruce W. Baker April D. Whicker Glenn Plumb 《Environmental management》1999,24(2):177-192
Cynomys spp.) have been labeled as keystone species because of their influence on biological diversity and ecosystem function. However,
the validity of several assumptions used to support keystone status is questionable. We review the strength of the evidence
and the magnitude of the prairie dog's effects on ecosystem structure and function. We use this review to reevaluate the keystone
role for prairie dogs. Our goal is to encourage sound management of the prairie dog ecosystem by improving the ecological
foundation of their keystone status. Our review confirms that prairie dogs affect a number of ecosystem-level functions but
that their influence on prairie vertebrates may be less than previously suggested. Species richness and abundance patterns
were variable among plants, mammals, and birds and were not consistently higher on prairie dog colonies compared to uncolonized
areas. In addition, only nine of the 208 species listed in the literature as observed on or near prairie dogs colonies had
quantitative evidence of dependence on prairie dogs. Abundance data indicated opportunistic use of colonies for an additional
20 species. A total of 117 species may have some relationship with prairie dogs, but we lacked sufficient data to evaluate
the strength of this relationship. The remaining 62 species may be accidental or alien to the system. Despite our conclusion
that some prairie dog functions may be smaller than previously assumed, collectively these functions are quite large compared
to other herbivores in the system. We suggest that prairie dogs also provide some unique functions not duplicated by any other
species and that continued decline of prairie dogs may lead to a substantial erosion of biological diversity and landscape
heterogeneity across prairie and shrub-steppe landscapes. Thus, we concur that keystone status for prairie dogs is appropriate
and may aid conservation efforts that help protect species dependent on prairie dogs and support other important ecosystem
functions. 相似文献
163.
Baker LA 《Chemosphere》2011,84(6):779-784
Achieving better understanding phosphorus (P) flows through urban ecosystems is needed to conserve P, as non-renewable phosphate rock deposits become depleted and the global human population increases. A baseline mass flow analysis (MFA) for P developed for the Twin Cities Watershed (TCW, which includes most of the Minneapolis-St. Paul metropolitan region) showed that most P input was stored in the system (65%) or leaked from it (31%); only 4% was deliberately exported as useful products. In a realistic, comprehensive conservation scenario P input was reduced by 15%; deliberate export of P in the form of sewage sludge, food waste, and landscape waste was 68% of P input. In this scenario, increased deliberate export was accomplished by decreasing leakage (to 9% of input) and storage (to 23% of input). If used as agricultural fertilizer, the deliberately exported P in the conservation scenario would support about half of the food production required by the TCW. 相似文献
164.
A.M. Helmus A.G. Fernald D.M. VanLeeuwen L.B. Abbott A.L. Ulery T.T. Baker 《Journal of the American Water Resources Association》2009,45(2):407-418
Abstract: Interactions between surface irrigation water, shallow ground water, and river water may have effects on water quality that are important for both drinking water supplies and the ecological function of rivers and floodplains. We investigated water quality in surface water and ground water, and how water quality is influenced by surface water inputs from an unlined irrigation system in the Alcalde Valley of the Rio Grande in northern New Mexico. From August 2005 to July 2006, we sampled ground water and surface water monthly and analyzed for concentrations of major cations and anions, specific conductance, pH, dissolved oxygen, and water levels. Results indicate that irrigation ditch seepage caused an increase in ground water levels and that the Rio Grande is a gaining stream in this region. Temporal and spatial differences were found in ion concentrations in shallow ground water as it flowed from under the ditch toward the river. Ground‐water ion concentrations were higher when the ditch was not flowing compared with periods during peak irrigation season when the ditch was flowing. Ditch inputs diluted ion concentrations in shallow ground water at well positions near the ditch. Specifically, lower ion concentrations were detected in ground water at well positions located near the ditch and river compared with well positions located in the middle of an agricultural field. Results from this project showed that ditch inputs influenced ion concentrations and were associated with ground‐water recharge. In arid region river valleys, careful consideration should be given to management scenarios that change seepage from irrigation systems, because in some situations reduced seepage could negatively affect ground‐water recharge and water quality. 相似文献
165.
Helen Ginzburg Xiaobo Liu Michael Baker Robert Shreeve R.K.M. Jayanty David Campbell 《Journal of the Air & Waste Management Association (1995)》2013,63(9):1062-1071
The Maryland State Highway Administration (SHA) monitoring program monitored the impact of vehicular emissions on the concentrations of the fine particles smaller than 2.5 microns (PM2.5). PM2.5 concentrations were monitored in close proximity to a highway in order to determine whether traffic conditions on the roadway impact concentrations at this location. The monitoring program attempted to connect monitored concentrations with the roadway traffic exhaust or with the other sources of PM2.5. PM2.5 concentrations were collected near the Capital Beltway (I-495/I-95) in Largo, Maryland. The monitoring program was launched on May 13, 2009 and continued through the end of 2012. Two co-located monitors, one for continuous PM2.5 measurements and the other for speciation measurements, were used in this program. Meteorological and traffic information was also continuously collected at or near the monitoring site. Additionally, data from the two other monitoring locations, one at the Howard University-Beltsville, MD and one at McMillan Reservoir, DC, was used for comparison with the data collected at the SHA monitoring location. The samples collected by the speciation monitor were analyzed at the RTI and DRI Laboratories to determine the composition and the sources of the collected PM2.5 samples. Based on the apportionment analysis, the contribution of roadway sources is about 12 to 17 percent of PM2.5 at the near-road site.Implications: PM2.5 monitoring at 150 m (approximately 500 feet) from a major highway in Maryland near Washington, DC, demonstrated that roadway traffic contributes to the total PM2.5 concentration near the roadway, but the contribution at such distance is small, in the order of 12–17% of the total. 相似文献
166.
Huynh TT Laidlaw WS Singh B Gregory D Baker AJ 《Environmental pollution (Barking, Essex : 1987)》2008,156(3):874-882
Heavy metal concentrations and pH of pore-water in contaminated substrates are important factors in controlling metal uptake by plants. We investigated the effects of phytoextraction on these properties in the solution phase of biosolids and diluted biosolids in a 12-month phytoextraction column experiment. Phytoextraction using Salix and Populus spp. temporarily decreased pore-water pH of the substrates over the experimental period followed by a return to initial pH conditions. Salix × reichardtii and Populus balsamifera effectively extracted Ni, Zn and Cd and actively mobilized these metals from the solid to the solution phase. S. × reichardtii had the stronger effect on mobilization of metals due to its larger root system. Phytoextraction did not affect Cu in the solution phase of the biosolids. Heavy metals were leached down to lower depths of the columns during the phytoextraction process. 相似文献
167.
The fluorescence excitation–emission matrix properties of 25 dissolved organic matter samples from three rivers and one lake are analysed. All sites are sampled in duplicate, and the 25 samples include ten taken from the lake site, and nine from one of the rivers, to cover variations in dissolved organic matter composition due to season and river flow. Fluorescence properties are compared to the functional properties of the dissolved organic matter; the functional assays provide quantitative information on photochemical fading, buffering capacity, copper binding, benzo[a]pyrene binding, hydrophilicity and adsorption to alumina. Optical (absorbance and fluorescence) characterization of the dissolved organic matter samples demonstrates that (1) peak C (excitation 300–350 nm; emission 400–460 nm) fluorescence emission wavelength; (2) the ratio of peak T (excitation 220–235 nm; emission 330–370 nm) to peak C fluorescence intensity; and (3) the peak C fluorescence intensity: absorbance at 340 nm ratio have strong correlations with many of the functional assays. Strongest correlations are with benzo[a]pyrene binding, alumina adsorption, hydrophilicity and buffering capacity, and in many cases linear regression equations with a correlation coefficient >0.8 are obtained. These optical properties are independent of freshwater dissolved organic carbon concentration (for concentrations <10 mg L−1) and therefore hold the potential for laboratory, field and on-line monitoring and prediction of organic matter functional properties. 相似文献
168.
The phytoextraction of Zn may be improved by applying N fertilizers to increase the biomass and Zn content of shoots. Rhizosphere-pH change from uptake of different N forms will affect Zn phyto-availability in the rhizosphere and Zn phytoextraction. This glasshouse study examined the effect of N form on Zn phytoextraction by Thlaspi caerulescens (Prayon). The plants were grown in a Zn-contaminated soil (total Zn 250 mg kg-1 soil; pHwater 5.7) and supplied with (NH4)2SO4, Ca(NO3)2 or urea [(NH2)2CO]. The form was maintained by applying the nitrification inhibitor dicyandiamide. A biodegradable chelator ethylenediaminedisuccinic acid (EDDS) was included for comparison. The addition of N doubled the shoot biomass. The highest shoot Zn content occurred in the Ca(NO3)2 treatment and was associated with the highest rhizosphere pH. The lowest shoot dry weight occurred in the EDDS treatment. The Zn concentration in the shoots increased as the rhizosphere pH increased. A significant correlation occurred between Ca and Zn concentrations in the shoots. This study demonstrated that Ca(NO3)2 is a more effective treatment than , urea or EDDS for enhancing Zn phytoextraction in a mildly acidic soil. 相似文献
169.
热带人工橡胶林异戊二烯排放通量的模式研究 总被引:7,自引:3,他引:7
2 0 0 2年 7月中旬 (湿季 ) ,我们利用快速异戊二烯系统对云南热带森林异戊二烯的排放通量进行了连续测量 ,同时对其影响因子光合有效辐射、气温、湿度、风等参数进行了观测 .研究表明 ,该地区人工橡胶林异戊二烯的排放有明显的日变化 ,云和降水可以明显减小异戊二烯的排放 .利用光合有效辐射守恒的观点处理与植物异戊二烯排放有关的过程 ,建立了一个计算异戊二烯排放的经验模式 ,计算值与观测值比较接近 .因此 ,以一定的物理原理和对实际大气状况观测资料的分析为基础 ,建立异戊二烯排放模式的方法是可行的 . 相似文献
170.
The possibility of in situ heavy metal decontamination of polluted soils using crops of metal-accumulating plants 总被引:8,自引:0,他引:8
A.J.M. Baker S.P. McGrath C.M.D. Sidoli R.D. Reeves 《Resources, Conservation and Recycling》1994,11(1-4)
The decontamination of soils and wastes polluted with heavy metals presents one of the most intractable problems for soil clean-up. Present technology relies upon metal extraction or immobilization processes, both of which are expensive and which remove all biological activity in the soil during decontamination. They may only be appropriate for small areas of valuable redevelopment land. In this paper the use of metal-accumulating plants is explored for the removal of metals from superficially-contaminated soils such as those resulting from the long-term application to land of metal-contaminated sewage sludges. Green remediation employs plants native to metalliferous soils with a capacity to bioaccumulate metals such as zinc and nickel to concentrations greater than 2% in the aerial plant dry matter (hyperaccumulators). Growing such plants under intensive crop conditions and harvesting the dry matter is proposed as a possible method of metal removal and for ‘polishing’ contaminated agricultural soils down to metal concentrations below statutory limits. Not only are the biological activity and physical structure of soils maintained but the technique is potentially cheap, visually unobtrusive and offers the possibility of biorecovery of metals. The limitations of the process are reviewed and the future requirements for the development of efficient phytoremediators are outlined. 相似文献