全文获取类型
收费全文 | 487篇 |
免费 | 7篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 23篇 |
废物处理 | 23篇 |
环保管理 | 133篇 |
综合类 | 48篇 |
基础理论 | 116篇 |
环境理论 | 1篇 |
污染及防治 | 96篇 |
评价与监测 | 42篇 |
社会与环境 | 13篇 |
灾害及防治 | 6篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 9篇 |
2017年 | 8篇 |
2016年 | 14篇 |
2015年 | 13篇 |
2014年 | 11篇 |
2013年 | 47篇 |
2012年 | 16篇 |
2011年 | 28篇 |
2010年 | 17篇 |
2009年 | 18篇 |
2008年 | 27篇 |
2007年 | 28篇 |
2006年 | 15篇 |
2005年 | 14篇 |
2004年 | 9篇 |
2003年 | 23篇 |
2002年 | 15篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 15篇 |
1997年 | 10篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 9篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 8篇 |
排序方式: 共有501条查询结果,搜索用时 147 毫秒
41.
J. Roger McHenry 《Journal of the American Water Resources Association》1974,10(2):329-337
ABSTRACT: Reservoirs, as well as lakes and estuaries, are subject to sediment accumulation. The rate at which sedimentation occurs is accelerated or diminished by man's activities. Acceptable rates of sedimentation are considered on the basis of costs of sediment storage and removal and a review of reservoirs constructed with sediment removal capabilities is given. The rates of reservoir sedimentation in the United States are summarized based on reliable data obtained from all sizes of reservoirs. Problems confronting the engineer concerning reservoir construction and maintenance are discussed on the basis of these data. 相似文献
42.
Fiona Curran Cournane Richard McDowell Roger Littlejohn Leo Condron 《Agriculture, ecosystems & environment》2011,140(1-2):264-272
Livestock grazing and treading is strongly linked to a decrease in freshwater quality and promotes eutrophication. A two-year field trial was carried out to investigate the influence cattle, sheep and deer have on soil physical quality and the loss of phosphorus (P) and suspended sediment (SS) in surface runoff. Surface runoff plots (4 m long by 1 m wide) were installed within areas designated as stock or ungrazed (control). Surface runoff was collected and analysed for concentrations and loads of P fractions (dissolved reactive P-DRP, dissolved unreactive P-DUP, total dissolved P-TDP, particulate P-PP and total P-TP) and SS. Grazed at equivalent stocking density, soil physical samples (macroporosity, bulk density, and saturated hydraulic conductivity Ksat) were taken after each grazing event (n = 11). Soil physical data indicated differences between cattle, sheep and deer with cattle having greater negative effects. However, these differences had no impact on P and SS losses between stock types in surface runoff. Significant relationships showed that an increase in macroporosity, Ksat, and time (days) since grazing decreased concentrations and loads of P and SS losses. A separate rainfall simulation study also revealed that an increase in simulated cattle treading intensity increased the volume of surface runoff and SS losses. Most surface runoff (> 90%) occurred in winter when soil moisture was at or above field capacity. A seasonal effect was observed and showed that although the greatest P loads occurred in winter, the greatest P concentrations occurred in summer months, under infiltration-excess conditions. These summer losses could pose a risk to receiving waterways because increased light and warmth may induce an algal response compared to winter. While there is limited scope to manage for infiltration-excess surface runoff losses from pasture, with most runoff occurring in winter, these findings reinforce the use of mitigation strategies such as restricted or nil grazing in winter when soil moisture has reached field capacity to minimise P and SS loss to surface water, regardless of stock type. 相似文献
43.
Predicted increases in coral disease outbreaks associated with climate change have implications for coral reef ecosystems
and the people and industries that depend on them. It is critical that coral reef managers understand these implications and
have the ability to assess and reduce risk, detect and contain outbreaks, and monitor and minimise impacts. Here, we present
a coral disease response framework that has four core components: (1) an early warning system, (2) a tiered impact assessment
program, (3) scaled management actions and (4) a communication plan. The early warning system combines predictive tools that
monitor the risk of outbreaks of temperature-dependent coral diseases with in situ observations provided by a network of observers
who regularly report on coral health and reef state. Verified reports of an increase in disease prevalence trigger a tiered
response of more detailed impact assessment, targeted research and/or management actions. The response is scaled to the risk
posed by the outbreak, which is a function of the severity and spatial extent of the impacts. We review potential management
actions to mitigate coral disease impacts and facilitate recovery, considering emerging strategies unique to coral disease
and more established strategies to support reef resilience. We also describe approaches to communicating about coral disease
outbreaks that will address common misperceptions and raise awareness of the coral disease threat. By adopting this framework,
managers and researchers can establish a community of practice and can develop response plans for the management of coral
disease outbreaks based on local needs. The collaborations between managers and researchers we suggest will enable adaptive
management of disease impacts following evaluating the cost-effectiveness of emerging response actions and incrementally improving
our understanding of outbreak causation. 相似文献
44.
The Bangladesh floods of 1984 in historical context 总被引:1,自引:0,他引:1
Roger Montgomery 《Disasters》1985,9(3):163-172
45.
Zhu J Wu X Miller C Yu F Chen P Ruan R 《Journal of environmental science and health. Part. B》2007,42(4):393-401
In this paper, continuous production of hydrogen through fermentation with liquid swine manure as substrate was researched using a semi-continuously fed fermenter (8 L in total volume and 4 L in working volume). The pH and temperature for the fermenter were controlled at 5.3 +/- 0.1 and 35 +/- 1 degrees C, respectively, throughout the experiment. Three hydraulic retention times (16, 20, and 24 h) were investigated for their impact on the efficiency and performance of the fermenter in terms of hydrogen yields. The results indicate that hydraulic retention time (HRT) has a strong influence on the fermenter performance. An increasing HRT would increase the variation in hydrogen concentration in the offgas. To produce hydrogen with a fairly consistent concentration, the HRT of the fermenter should not exceed 16 h, which, however, did not appear to be short enough to control methanogenesis because the offgas still contained about 5% methane. When methane content in the offgas exceeded 2%, an inverse linear relationship between hydrogen and methane was observed with a correlation coefficient of 0.9699. To increase hydrogen content in the offgas, methane production has to be limited to below 2%. Also, keeping oxygen content in the fermenter below 1.5% would increase the hydrogen concentration to over 15%. The product to substrate ratio was found to be around 50% for the fermenter system studied, evidenced by the observation that for every 6 liters of manure fermented, 3 liters of pure hydrogen were produced, which was significant and encouraging. 相似文献
46.
Successful remediation of contaminated soils is often limited by the low bioavailability of hydrophobic pollutants, which may slow the process significantly. In this study we investigated the benefits of high temperature in enhancing hydrocarbon degradation rates and evaluated the effect of different biostimulants. Hexadecane polluted soil microcosms with various amendments were incubated both at 60 degrees C and room temperature (18 degrees C) and analyzed periodically up to 40d for the degradation of hydrocarbon and the response of the microbial population. Natural attenuation showed a satisfactory intrinsic degradative capability at 60 degrees C and the addition of inorganic N, P and K increased the degradation rates by 10%. The addition of rhamnolipid biosurfactant further enhanced the bioavailability of alkane to microbial degradation resulting in up to 71% removal at 60 degrees C and 42% at 18 degrees C. Significant input to hexadecane degradation occurred at 60 degrees C (70%) as a result of the bioaugmentation with thermophilic Geobacillus thermoleovorans T80, which did not take place at 18 degrees C. Coupling high temperature to all amendments resulted in 90% removal of the hexadecane from soil after 40d which was also accompanied with an increase in bacterial numbers. The results suggest that thermally enhanced bioremediation may be an efficient technology for the treatment of hydrocarbon-contaminated soils. 相似文献
47.
48.
Berry ED Woodbury BL Nienaber JA Eigenberg RA Thurston JA Wells JE 《Journal of environmental quality》2007,36(6):1873-1882
Determining the survival of zoonotic pathogens in livestock manure and runoff is critical for understanding the environmental and public health risks associated with these wastes. The occurrence and persistence of the bacterial pathogens Escherichia coli O157:H7 and Campylobacter spp. in a passive beef cattle feedlot runoff control-vegetative treatment system were examined over a 26-mo period. Incidence of the protozoans Cryptosporidium spp. and Giardia spp. was also assessed. The control system utilizes a shallow basin to collect liquid runoff and accumulate eroded solids from the pen surfaces; when an adequate liquid volume is attained, the liquid is discharged from the basin onto a 4.5-ha vegetative treatment area (VTA) of bromegrass which is harvested as hay. Basin discharge transported E. coli O157, Campylobacter spp., and generic E. coli into the VTA soil, but without additional discharge from the basin, the pathogen prevalences decreased over time. Similarly, the VTA soil concentrations of generic E. coli initially decreased rapidly, but lower residual populations persisted. Isolation of Cryptosporidium oocysts and Giardia cysts from VTA samples was infrequent, indicating differences in sedimentation and/or transport in comparison to bacteria. Isolation of generic E. coli from freshly cut hay from VTA regions that received basin discharge (12 of 30 vs. 1 of 30 control samples) provided evidence for the risk of contamination; however, neither E. coli O157 or Campylobacter spp. were recovered from the hay following baling. This work indicates that the runoff control system is effective for reducing environmental risk by containing and removing pathogens from feedlot runoff. 相似文献
49.
Sand-sized particles (>63 microm) in whole storm water samples collected from urban runoff have the potential to produce data with substantial bias and/or poor precision both during sample splitting and laboratory analysis. New techniques were evaluated in an effort to overcome some of the limitations associated with sample splitting and analyzing whole storm water samples containing sand-sized particles. Wet-sieving separates sand-sized particles from a whole storm water sample. Once separated, both the sieved solids and the remaining aqueous (water suspension of particles less than 63 microm) samples were analyzed for total recoverable metals using a modification of USEPA Method 200.7. The modified version digests the entire sample, rather than an aliquot, of the sample. Using a total recoverable acid digestion on the entire contents of the sieved solid and aqueous samples improved the accuracy of the derived sediment-associated constituent concentrations. Concentration values of sieved solid and aqueous samples can later be summed to determine an event mean concentration. 相似文献
50.
Lisa G. Shaffer Justine Coppinger S. Annie Morton Sarah Alliman Jessica Burleson Ryan Traylor Cathryn Walker Steve Byerly Allen N. Lamb Roger Schultz J. Britt Ravnan Catherine D. Kashork Beth S. Torchia Scott Sulpizio Kyle Sundin Mack Schermer Karl Adler Stephanie Dallaire Blake C. Ballif 《黑龙江环境通报》2011,31(8):778-787