全文获取类型
收费全文 | 57篇 |
免费 | 2篇 |
专业分类
安全科学 | 7篇 |
废物处理 | 2篇 |
环保管理 | 11篇 |
综合类 | 10篇 |
基础理论 | 19篇 |
污染及防治 | 6篇 |
评价与监测 | 3篇 |
社会与环境 | 1篇 |
出版年
2019年 | 1篇 |
2017年 | 1篇 |
2016年 | 6篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 4篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 1篇 |
2007年 | 4篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2003年 | 3篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有59条查询结果,搜索用时 31 毫秒
41.
42.
Kinneret Yoktan Eli Geffen Amiyaal Ilany Yoram Yom-Tov Adit Naor Noam Leader 《Behavioral ecology and sociobiology》2011,65(7):1389-1402
At least four hypotheses have been suggested to explain the formation and maintenance of song dialects among birds: historic
processes (epiphenomenon), genetic or local adaptation, acoustic adaptation, and social adaptation. We studied spatial and
temporal distribution of dialect in the orange-tufted sunbird (Nectarinia osea), a small nectarivorous bird that expanded its breeding range in Israel during the past 100 years from the southern part
of Rift Valley to the entire country. Sunbird range expansion was concurrent with the establishment of many small settlements
with an ethos of gardening, which introduced many ornithophilous plants. We recorded songs and genetically screened individual
sunbirds in 29 settlements distributed across a 380 km north–south gradient along the Rift Valley. We show that dialects cluster
together into geographical regions in 70% of cases, a moderate concurrence to geography. Settlement establishment date, geographical
position, and genetic distance between local populations (i.e., settlements) were all poor predictors for the variance among
song dialects. The specific effect of habitat was not tested because all sampled localities were similar in their physical
and acoustic properties. Using a network analysis, we show that dialects seem to aggregate into several network communities,
which clustered settlement populations from several regions. Our results are best explained by either the epiphenomenon hypothesis
or the social adaptation hypothesis, but at present our data cannot state unequivocally which of these hypotheses is better
supported. Last, we discovered a negative association between network centrality and genetic diversity, a pattern that requires
further examination in other systems. 相似文献
43.
44.
45.
Long‐Term Trends in Streamflow and Precipitation in Northwest California and Southwest Oregon, 1953‐2012
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)
J. Eli Asarian Jeffrey D. Walker 《Journal of the American Water Resources Association》2016,52(1):241-261
Using nonparametric Mann‐Kendall tests, we assessed long‐term (1953‐2012) trends in streamflow and precipitation in Northern California and Southern Oregon at 26 sites regulated by dams and 41 “unregulated” sites. Few (9%) sites had significant decreasing trends in annual precipitation, but September precipitation declined at 70% of sites. Site characteristics such as runoff type (groundwater, snow, or rain) and dam regulation influenced streamflow trends. Decreasing streamflow trends outnumbered increasing trends for most months except at regulated sites for May‐September. Summer (July‐September) streamflow declined at many sites, including 73% of unregulated sites in September. Applying a LOESS regression model of antecedent precipitation vs. average monthly streamflow, we evaluated the underlying streamflow trend caused by factors other than precipitation. Decreasing trends in precipitation‐adjusted streamflow substantially outnumbered increasing trends for most months. As with streamflow, groundwater‐dominated sites had a greater percent of declining trends in precipitation‐adjusted streamflow than other runoff types. The most pristine surface‐runoff‐dominated watersheds within the study area showed no decreases in precipitation‐adjusted streamflow during the summer months. These results suggest that streamflow decreases at other sites were likely due to more increased human withdrawals and vegetation changes than to climate factors other than precipitation quantity. 相似文献
46.
Aerosol Particle Processing and Removal by Fogs: Observations in Chemically Heterogeneous Central California Radiation Fogs 总被引:4,自引:0,他引:4
Collett Jeffrey L. Sherman D. Eli Moore Katharine F. Hannigan Michael P. Lee Taehyoung 《Water, Air, & Soil Pollution: Focus》2001,1(5-6):303-312
Fog composition and deposition fluxes of fog waterand fog solutes were measured in six radiation fogevents in San Joaquin Valley, California duringwinter 1998/1999. Measurements made at 2 hrintervals with 0.30 m2 and 0.06 m2 Teflondeposition plates yielded excellent reproducibility(relative standard deviations of 3.8–6.0%) forwater, nitrate, sulfate and ammonium. Water fluxesmeasured at 5 min intervals with a recordingbalance agreed well with the deposition platemeasurements before 8:00 AM. After 8:00 AMevaporation proved problematic. The averagedeposition velocity from the study for fog nitrate(3.8 cm s-1) was less than those for fogsulfate (5.1 cm s-1) and ammonium (6.7 cms-1). All three species generally exhibitedsmaller deposition velocities than fog water. Thespecies dependent trend in deposition velocitieswas consistent with preferential enrichment ofthese species in small fog drops (nitrate > sulfate> ammonium). 相似文献
47.
Weekly variation of atmospheric particle micromorphology and chemistry in Brussels urban environment
Eli Zaady D. Carati L. Brenig P. Vanderstraeten Y. Lénelle A. Meurrens Z. Y. Offer 《Environmental monitoring and assessment》2010,169(1-4):45-54
The purpose of this study was to measure the impact of urban activities on airborne particle dynamics during weekend periods in Brussels urban area. Differences in the granulometry and micromorphology between particles sampled on working days and weekends were studied. We quantified the area, size, number, and the chemistry parameters of the airborne particles and compared between Saturday, Sunday, and Monday. We report and analyze data on airborne particles up to PM10, measured in the Brussels region from October 2002 to September 2003. Our investigation reveals detailed information regarding chemical composition of the airborne particles over the weekend period in the Brussels urban area. Furthermore, the majority of the airborne particles in the Brussels region may belong to sources geographically outside the (in situ) Brussels area. 相似文献
48.
We examined constraints on soil CO2 respiration in natural oak woodlands, and adjacent vineyards that were converted approximately 30 yr ago from oak woodlands, in the Oakville Region of Napa Valley, California. All sites were located on the same soil type, a Bale (variant) gravelly loam (fine-loamy, mixed, superactive, thermic Cumulic Ultic Haploxeroll) and dominated by C3 vegetation. Seasonal soil CO2 efflux was greatest at the oak woodland sites, although during the summer drought the rates of soil CO2 efflux measured from oak sites were generally similar to those measured from the vineyards. Soil profile CO2 concentrations at the oak woodland sites were lower below 15 cm despite higher CO2 efflux rates. Soil gas diffusion coefficients for oak sites were larger than for vineyard sites, and this indicated that the apparent discrepancy in soil profile carbon dioxide concentration ([CO2]) may be caused by a diffusion limitation. Soil profile [CO2] and delta13C values showed substantial temporal changes over the course of a year. Vineyard soil CO2 was more depleted in 13CO2 below 25 cm in the soil profile during the active growing season as indicated by more negative delta13C ratios. This result indicated that different C sources were being oxidized in vineyard soils. Annual C losses were less from vineyard soils (7.02 +/- 0.58 Mg C ha(-1) yr(-1)) as compared to oak soils (15.67 +/- 1.44 Mg C ha(-1) yr(-1)), and both were comparable to losses reported in previous investigations. 相似文献
49.
An extremely acidic, heavy metal-rich sludge (pH=-1.2) was scrubbed with a Class-F fly ash in order to simultaneously neutralize the acidity and stabilize the heavy metals contained in both wastes. This paper outlines the leaching behavior of the aggregate material generated by scrubbing. For proper fly ash/sludge ratios, the fly ash acted as an outstanding neutralizer for the acidic waste. Leaching of heavy metals from the aggregate samples was below the environmental limits within a pH range between 3 and 9. Subsequent washing of the leached aggregate with acidic CALWET solutions did not result in an additional release of heavy metals. It is proposed that coordinative bonding of the metal cations onto neutral surface sites and electrostatic adsorption led to stabilization of the heavy metals within the aggregate structure below hydrolysis pHs. 相似文献
50.
Prior residency advantages have been explained by an asymmetry between the ‘owner’ and the ‘intruder’ in fighting ability
(resource-holding potential) or motivation (value asymmetry (VA)). Here, we tested for the extent of prior residence effects
in individually tagged Atlantic salmon juveniles being released in two bouts (4 days apart) during spring along a natural
stream, and recaptured 3 months later. A prior residency advantage was detected both in terms of body growth, energy density
and male gonad size. As we controlled for effects of initial body size, which correlates with dominance, these findings are
in accordance with the VA hypothesis. The growth advantage of first arrivals also increased with local shelter abundance in
the stream, which can be expected if a higher resource value of the habitat results in a higher defence motivation. We also
found a prior residence effect on spatial distribution, with the second arrivals within each release site being recaptured
further downstream. No effect on apparent survival rates was found. The observed reduced growth and energy density may have
fitness consequences for the second arrivals, both in terms of lower winter survival rates and later age at maturity. For
mature male parr, both decreased body and gonad growth may give an additional disadvantage through reduced fertilization rates
during breeding. These costs may help to explain the tendency for stationary behaviour of stream salmonids, as the potential
benefits of moving into less crowded areas would be reduced by the risk of becoming an intruder. Prior residence effects may
therefore have influenced the evolution of movement behaviour in these organisms. 相似文献