全文获取类型
收费全文 | 1828篇 |
免费 | 16篇 |
国内免费 | 59篇 |
专业分类
安全科学 | 174篇 |
废物处理 | 34篇 |
环保管理 | 502篇 |
综合类 | 548篇 |
基础理论 | 186篇 |
环境理论 | 1篇 |
污染及防治 | 156篇 |
评价与监测 | 68篇 |
社会与环境 | 82篇 |
灾害及防治 | 152篇 |
出版年
2023年 | 13篇 |
2022年 | 10篇 |
2021年 | 24篇 |
2020年 | 44篇 |
2019年 | 14篇 |
2018年 | 23篇 |
2017年 | 43篇 |
2016年 | 53篇 |
2015年 | 49篇 |
2014年 | 62篇 |
2013年 | 86篇 |
2012年 | 46篇 |
2011年 | 121篇 |
2010年 | 63篇 |
2009年 | 96篇 |
2008年 | 97篇 |
2007年 | 84篇 |
2006年 | 81篇 |
2005年 | 58篇 |
2004年 | 67篇 |
2003年 | 96篇 |
2002年 | 69篇 |
2001年 | 57篇 |
2000年 | 64篇 |
1999年 | 53篇 |
1998年 | 60篇 |
1997年 | 54篇 |
1996年 | 56篇 |
1995年 | 47篇 |
1994年 | 29篇 |
1993年 | 33篇 |
1992年 | 20篇 |
1991年 | 14篇 |
1990年 | 14篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 12篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 10篇 |
1983年 | 9篇 |
1982年 | 11篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有1903条查询结果,搜索用时 31 毫秒
121.
This paper develops a method for identifying and assessing long-term supply risks for mineral raw materials. The method is based on a combined evaluation of past and future supply and demand trends. By analysing raw material boom and bust cycles over the past 50 years, we have quantified indicators and defined benchmarks for identifying critical market situations. By applying the method, risks for supply shortage may be identified at an early stage. In addition, a numerical evaluation model has been developed for better comparison between various mineral raw materials. Compared to other assessment methods this method uses specific benchmarks for each raw material to better assess supply risks. The method is embedded within a systematic and comprehensive analytical approach. 相似文献
122.
E. Smith R. Gordon C. Bourque A. Campbell S. Génermont P. Rochette M. Mkhabela 《Journal of environmental management》2009
A need exists to improve the utilization of manure nutrients by minimizing NH3 emissions from land application of manure. Management strategies to reduce NH3 emissions are available; however, few have been validated under Canadian conditions. A well tested and accurate simulation model, however, can help overcome this challenge by determining appropriate management strategies for a given set of field conditions. 相似文献
123.
Silvina Vargas Gil Analia Becker Claudio Oddino Mónica Zuza Adriana Marinelli Guillermo March 《Environmental management》2009,44(2):378-386
Soil microbial populations can fluctuate in response to environmental changes and, therefore, are often used as biological
indicators of soil quality. Soil chemical and physical parameters can also be used as indicators because they can vary in
response to different management strategies. A long-term field trial was conducted to study the effects of different tillage
systems (NT: no tillage, DH: disc harrow, and MP: moldboard plough), P fertilization (diammonium phosphate), and cattle grazing
(in terms of crop residue consumption) in maize (Zea mays L.), sunflower (Heliantus annuus L.), and soybean (Glycine max L.) on soil biological, chemical, and physical parameters. The field trial was conducted for four crop years (2000/2001,
2001/2002, 2002/2003, and 2003/2004). Soil populations of Actinomycetes, Trichoderma spp., and Gliocladium spp. were 49% higher under conservation tillage systems, in soil amended with diammonium phosphate (DAP) and not previously
grazed. Management practices also influenced soil chemical parameters, especially organic matter content and total N, which
were 10% and 55% higher under NT than under MP. Aggregate stability was 61% higher in NT than in MP, 15% higher in P-fertilized
soil, and also 9% higher in not grazed strips, bulk density being 12% lower in NT systems compared with MP. DAP application
and the absence of grazing also reduced bulk density (3%). Using conservation tillage systems, fertilizing crops with DAP,
and avoiding grazing contribute to soil health preservation and enhanced crop production. 相似文献
124.
Agri-environment programs aim to secure environmental and social stewardship services through payments to farmers. A critical
component of many agri-environment programs is an agri-environment index (AEI) used to quantify benefits and target investments.
An AEI will typically comprise multiple indicators, which are weighted and combined using a utility function, to measure the
benefit of investment options (e.g., projects, farms, regions). This article presents a review of AEIs with 11 case studies
from agri-environment programs in the United States, Australia, and the United Kingdom. We identify a generic procedure used
to define AEIs and explore the implications of alternative methodological approaches. We conclude that AEIs have become an
extremely important policy instrument and make suggestions for their improvement. 相似文献
125.
A framework for the protection of the general public has been in existence for a very long time, although steps have recently been made by the ICRP to ensure that it is more fully comprehensive with regard to all actual and potential exposure situations. Protection of the environment, however, has only recently begun to be addressed in a structured manner, and is still an evolving subject. Nevertheless, it needs to be centred around some form of parallel framework to that which has evolved for the protection of human beings, although clearly on a different scale. It also needs to be embedded within the basic science of radiobiology, and form a central part of radioecology. 相似文献
126.
We need to ensure the sustainable management of advanced materials, such as purified silicon, that contribute to a low-carbon
society. Because a drastic increase in the demand for photovoltaic (PV) systems is tightening the supply of silicon for PV
cells, the sustainability of silicon feedstock needs to be explored. For this purpose, a material flow analysis of silicon
in Japan from 1996 to 2006 is presented in this paper. Our analysis finds that rapid growth in demand for polycrystalline
silicon (pc-silicon) and single crystalline silicon (sc-silicon) has changed the structure of the purified silicon supply.
The strong demand for purified silicon for solar cells is responsible for this change. While off-grade silicon obtained as
a by-product of electronic-grade silicon (EG-Si) covered the demand for solar sells before 2000, pc-silicon is currently produced
independently for solar cells via an energy-intensive process. Analysis of the resource effective-use index (REI), which indicates
how effectively purified silicon is used, shows progress in the effective use of pc- and sc-silicon. REI analysis indicates
that the effective use of pc-silicon is reaching a maximum, while the effective use of sc-silicon is advancing, with a corresponding
increase in price. To ensure a sustainable supply of silicon feedstock, this paper proposes four solutions: (1) production
of solar-grade pc-silicon by a less costly and less energy-consuming method; (2) reduction in the amount of crystalline silicon
per watt in solar cells; (3) acceleration of the development and deployment of other solar cell types; and (4) reuse and recycling
of solar cells in the future. 相似文献
127.
Thomas Schwartz Christina Jungfer Stefan Heißler Frank Friedrich Werner Faubel Ursula Obst 《Chemosphere》2009,77(2):249-257
DNA-based population analysis was applied in combination with Raman spectrometry and Environmental Scanning Electron Microscopy for the characterisation of natural biofilms from sand and activated carbon filters operated for a long term at a municipal waterworks. Whereas the molecular biology polymerase chain reaction combined with denaturing gradient gel electrophoresis approach provides a deeper insight into the bacterial biofilm diversities, Raman spectrometry analyses the chemical composition of the extracellular polymer substances (EPS), microorganisms embedded in EPS as well as other substances inside biofilm (inorganic compounds and humic substances). Microscopy images the spatial distribution of biofilms on the two different filter materials. In addition, bacterial bulk water populations were compared with biofilm consortia using the molecular fingerprint technique mentioned.Population analysis demonstrated the presence of more diverse bacterial species embedded in a matrix of EPS (polysaccharides, peptides, and nucleic acids) on the sand filter materials. In contrast to this, activated carbon granules were colonised by reduced numbers of bacterial species in biofilms. Besides α-, β-, and γ-Proteobacteria, a noticeable specific colonisation with Actinobacteria was found on activated carbon particles. Here, the reduced biofilm formation came along with a decreased EPS synthesis. The taxonomy profiles of the different biofilms revealed up to 60% similarity on the same filter materials and 32% similarity of different materials. Similarity of adherent communities from filter materials and bulk water populations from the filter effluent varied between 36% and 58% in sand filters and 6–40% in granular activated carbon filters.The biofilm investigation protocols are most crucial to subsequent acquisition of knowledge on biofilm dynamics and bacterial contributions to transformation or adsorption processes in waterworks facilities. 相似文献
128.
Nadeem W. Shah Steven F. Thornton Simon H. Bottrell Michael J. Spence 《Journal of contaminant hydrology》2009,103(3-4):119-133
The potential for aerobic biodegradation of MTBE in a fractured chalk aquifer is assessed in microcosm experiments over 450 days, under in situ conditions for a groundwater temperature of 10 °C, MTBE concentration between 0.1 and 1.0 mg/L and dissolved O2 concentration between 2 and 10 mg/L. Following a lag period of up to 120 days, MTBE was biodegraded in uncontaminated aquifer microcosms at concentrations up to 1.2 mg/L, demonstrating that the aquifer has an intrinsic potential to biodegrade MTBE aerobically. The MTBE biodegradation rate increased three-fold from a mean of 6.6 ± 1.6 μg/L/day in uncontaminated aquifer microcosms for subsequent additions of MTBE, suggesting an increasing biodegradation capability, due to microbial cell growth and increased biomass after repeated exposure to MTBE. In contaminated aquifer microcosms which also contained TAME, MTBE biodegradation occurred after a shorter lag of 15 or 33 days and MTBE biodegradation rates were higher (max. 27.5 μg/L/day), probably resulting from an acclimated microbial population due to previous exposure to MTBE in situ. The initial MTBE concentration did not affect the lag period but the biodegradation rate increased with the initial MTBE concentration, indicating that there was no inhibition of MTBE biodegradation related to MTBE concentration up to 1.2 mg/L. No minimum substrate concentration for MTBE biodegradation was observed, indicating that in the presence of dissolved O2 (and absence of inhibitory factors) MTBE biodegradation would occur in the aquifer at MTBE concentrations (ca. 0.1 mg/L) found at the front of the ether oxygenate plume. MTBE biodegradation occurred with concomitant O2 consumption but no other electron acceptor utilisation, indicating biodegradation by aerobic processes only. However, O2 consumption was less than the stoichiometric requirement for complete MTBE mineralization, suggesting that only partial biodegradation of MTBE to intermediate organic metabolites occurred. The availability of dissolved O2 did not affect MTBE biodegradation significantly, with similar MTBE biodegradation behaviour and rates down to ca. 0.7 mg/L dissolved O2 concentration. The results indicate that aerobic MTBE biodegradation could be significant in the plume fringe, during mixing of the contaminant plume and uncontaminated groundwater and that, relative to the plume migration, aerobic biodegradation is important for MTBE attenuation. Moreover, should the groundwater dissolved O2 concentration fall to zero such that MTBE biodegradation was inhibited, an engineered approach to enhance in situ bioremediation could supply O2 at relatively low levels (e.g. 2–3 mg/L) to effectively stimulate MTBE biodegradation, which has significant practical advantages. The study shows that aerobic MTBE biodegradation can occur at environmentally significant rates in this aquifer, and that long-term microcosm experiments (100s days) may be necessary to correctly interpret contaminant biodegradation potential in aquifers to support site management decisions. 相似文献
129.
David W. Ostendorf Baoshan Xing Niki Kallergis 《Journal of contaminant hydrology》2009,106(3-4):118-130
At a former wood preservation plant severely contaminated with coal tar oil, in situ bulk attenuation and biodegradation rate constants for several monoaromatic (BTEX) and polyaromatic hydrocarbons (PAH) were determined using (1) classical first order decay models, (2) Michaelis–Menten degradation kinetics (MM), and (3) stable carbon isotopes, for o-xylene and naphthalene. The first order bulk attenuation rate constant for o-xylene was calculated to be 0.0025 d− 1 and a novel stable isotope-based first order model, which also accounted for the respective redox conditions, resulted in a slightly smaller biodegradation rate constant of 0.0019 d− 1. Based on MM-kinetics, the o-xylene concentration decreased with a maximum rate of kmax = 0.1 µg/L/d. The bulk attenuation rate constant of naphthalene retrieved from the classical first order decay model was 0.0038 d− 1. The stable isotope-based biodegradation rate constant of 0.0027 d− 1 was smaller in the reduced zone, while residual naphthalene in the oxic part of the plume further downgradient was degraded at a higher rate of 0.0038 d− 1. With MM-kinetics a maximum degradation rate of kmax = 12 µg/L/d was determined. Although best fits were obtained by MM-kinetics, we consider the carbon stable isotope-based approach more appropriate as it is specific for biodegradation (not overall attenuation) and at the same time accounts for the dominant electron-accepting process. For o-xylene a field based isotope enrichment factor εfield of − 1.4 could be determined using the Rayleigh model, which closely matched values from laboratory studies of o-xylene degradation under sulfate-reducing conditions. 相似文献
130.
Convergence of Culture, Ecology, and Ethics: Management of Feral Swamp Buffalo in Northern Australia
Glenn Albrecht Clive R. McMahon David M. J. S. Bowman Corey J. A. Bradshaw 《Journal of Agricultural and Environmental Ethics》2009,22(4):361-378
This paper examines the identity of Asian swamp buffalo (Bubalus bubalis) from different value orientations. Buffalo were introduced into Northern (Top End) Australia in the early nineteenth century.
A team of transdisciplinary researchers, including an ethicist, has been engaged in field research on feral buffalo in Arnhem
Land over the past three years. Using historical documents, literature review, field observations, interviews with key informants,
and interaction with the Indigenous land owners, an understanding of the diverse views on the scientific, cultural, and economic
significance of buffalo was obtained. While the diverse stakeholders in buffalo exploitation and management have historically
delivered divergent value orientations on the nature of the human–buffalo relationship, we argue that over time there is the
possibility of values and ethical convergence. Such convergence is possible via transdisciplinary and transcultural agreement
on the value stances that constitute the construction of the being or identity of buffalo in the face of the overwhelming
need to manage population density and gross numbers. 相似文献