全文获取类型
收费全文 | 462篇 |
免费 | 14篇 |
国内免费 | 60篇 |
专业分类
安全科学 | 25篇 |
废物处理 | 7篇 |
环保管理 | 33篇 |
综合类 | 163篇 |
基础理论 | 46篇 |
污染及防治 | 111篇 |
评价与监测 | 137篇 |
社会与环境 | 11篇 |
灾害及防治 | 3篇 |
出版年
2024年 | 2篇 |
2023年 | 12篇 |
2022年 | 12篇 |
2021年 | 6篇 |
2020年 | 22篇 |
2019年 | 14篇 |
2018年 | 13篇 |
2017年 | 11篇 |
2016年 | 24篇 |
2015年 | 19篇 |
2014年 | 16篇 |
2013年 | 29篇 |
2012年 | 29篇 |
2011年 | 43篇 |
2010年 | 25篇 |
2009年 | 37篇 |
2008年 | 34篇 |
2007年 | 26篇 |
2006年 | 25篇 |
2005年 | 14篇 |
2004年 | 11篇 |
2003年 | 8篇 |
2002年 | 15篇 |
2001年 | 14篇 |
2000年 | 12篇 |
1999年 | 9篇 |
1998年 | 13篇 |
1997年 | 11篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 7篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有536条查询结果,搜索用时 0 毫秒
531.
Herzog F Lausch A Müller E Thulke HH Steinhardt U Lehmann S 《Environmental management》2001,27(1):91-107
This investigation tested the usefulness of geometry-based landscape metrics for monitoring landscapes in a heavily disturbed
environment. Research was carried out in a 75 sq km study area in Saxony, eastern Germany, where the landscape has been affected
by surface mining and agricultural intensification. Landscape metrics were calculated from digital maps (1912, 1944, 1973,
1989) for the entire study area and for subregions (river valleys, plains), which were defined using the original geology
and topography of the region. Correlation and factor analyses were used to select a set of landscape metrics suitable for
landscape monitoring. Little land-use change occurred in the first half of the century, but political decisions and technological
developments led to considerable change later. Metrics showed a similar pattern with almost no change between 1912 and 1944,
but dramatic changes after 1944. Nonparametric statistical methods were used to test whether metrics differed between river
valleys and plains. Significant differences in the metrics for these regions were found in the early maps (1912, 1944), but
these differences were not significant in 1973 or 1989. These findings indicate that anthropogenic influences created a more
homogeneous landscape. 相似文献
532.
考察了便携式分光光度计对地表水中化学需氧量(COD)、氨氮(NH_3-N)、氟化物(F~-)、总磷(TP)和六价铬(Cr~(6+))的应急监测的适用性。对方法精密度和准确度进行测定,并将便携式方法与实验室方法的测定结果进行比对。结果表明,方法精密度为2.3%~7.4%,标准样品除Cr6+外,其他均在保证值范围内;加标回收率为86.0%~110%,2种方法比对的相对偏差为2.9%~6.4%。该方法精密度与准确度良好,可以较好地应用于地表水环境应急监测中。 相似文献
533.
《Environmental Forensics》2013,14(3):175-189
During the last decade, the fuel oxygenate methyl tertiary butyl ether (MTBE) has received widespread attention as a potential threat to water quality, primarily due to leaking underground gasoline storage tanks and watercraft with two-stroke engines. In this article, we examine the annual detection frequency, number of new source detections, and concentration of MTBE detected in California's public drinking water groundwater and surface water sources from 1995 to 2002. This work builds on our previous evaluations of California's water quality monitoring database. However, it is unique in that it includes separate evaluations for groundwater and surface water sources that are of greatest concern to regulators, and which are likely being used for current public consumption. Our evaluations also include full-year data for 2002 (which have not been published previously) and an analysis of how the sampling and reported detections of MTBE vary by geographic location. We find that MTBE was generally detected (at any level) in approximately 0.5-0.9% and 0.2-0.4% of all groundwater sources assuming a one-detection and two-detection criterion, respectively. The overall detection frequency for MTBE in surface water sources is significantly higher than for groundwater sources, although these surface water detections appear to have substantially declined since 1996 (e.g., 7-9% for all surface water sources during 1996 to 1999 and 4% for all surface water sources during 2000 to 2002, assuming a one-detection criterion). The detection frequency of MTBE concentrations at or above the state drinking water standards in all drinking water sources (both groundwater and surface water sources) and the subset of drinking water sources that are likely to currently be delivered to consumers is markedly lower (and often zero). Despite the significant increase in water sampling over time, the number of new drinking water sources found to contain MTBE in California has not increased at the same rate and appears to have remained relatively stable or to have decreased since 1998. The data also show that nearly all of the 58 counties in California have routinely sampled at least some of their groundwater and surface water sources for MTBE over the last 8 years. Geographical evaluations show that MTBE has been detected (at least once) in groundwater sources in 34 counties and in surface water sources in 18 counties but has only been detected routinely (i.e., for 3 or more years) in 16 and 7 counties, respectively. Detected concentrations of MTBE are also generally below state drinking water standards, particularly for surface water sources. In short: (1) MTBE is rarely found in California groundwater or surface water sources that are of greatest concern to regulators or the public, and (2) drinking water detections of MTBE are expected to decline in the future due to the pending phase-out of MTBE and recent regulatory programs aimed at controlling gasoline releases from underground storage tanks and two-stroke-engine watercraft. 相似文献
534.
535.
The effect of monoammonium phosphate (NH4H2PO4) particles on 5 μm aluminum dust flames is investigated experimentally and computationally. NH4H2PO4 in three particle size is employed to determine the inhibition efficiency on aluminum flame propagation. Flame inhibition mechanism considering both gas and surface chemistry of aluminum particles is developed. Results show that the inhibition effectiveness monotonously increases as NH4H2PO4 particle size is reduced to 25 μm. Flame morphology and flame microstructure change with the addition of different particle size NH4H2PO4. Small NH4H2PO4 particles within the range studied have a greater reduction in average flame propagation compared to the coarser one. Meanwhile, the fine NH4H2PO4 particles almost decompose completely during the penetration of aluminum flame and then undergo a sufficient chemical interaction with the flame. The simulations indicate that the decomposition products of NH4H2PO4 particles obstruct the oxidation of aluminum particles through flame radical consumption. Additionally, the addition of NH4H2PO4 can reduce the vaporization rate and surface reaction rate of aluminum particles. 相似文献
536.
Birnessite (δ-Mn(IV)O2) is a great manganese (Mn) adsorbent for dissolved divalent metals. In this study, we investigated the coprecipitation mechanism of δ-MnO2 in the presence of Zn(II) and an oxidizing agent (sodium hypochlorite) under two neutral pH values (6.0 and 7.5). The mineralogical characteristics and Zn–Mn mixed products were compared with simple surface complexation by adsorption modeling and structural analysis. Batch coprecipitation experiments at different Zn/Mn molar ratios showed a Langmuir-type isotherm at pH 6.0, which was similar to the result of adsorption experiments at pH 6.0 and 7.5. X-ray diffraction and X-ray absorption fine structure analysis revealed triple-corner-sharing inner-sphere complexation on the vacant sites was the dominant Zn sorption mechanism on δ-MnO2 under these experimental conditions. A coprecipitation experiment at pH 6.0 produced some hetaerolite (ZnMn(III)2O4) and manganite (γ-Mn(III)OOH), but only at low Zn/Mn molar ratios (< 1). These secondary precipitates disappeared because of crystal dissolution at higher Zn/Mn molar ratios because they were thermodynamically unstable. Woodruffite (ZnMn(IV)3O7•2H2O) was produced in the coprecipitation experiment at pH 7.5 with a high Zn/Mn molar ratio of 5. This resulted in a Brunauer–Emmett–Teller (BET)-type sorption isotherm, in which formation was explained by transformation of the crystalline structure of δ-MnO2 to a tunnel structure. Our experiments demonstrate that abiotic coprecipitation reactions can induce Zn–Mn compound formation on the δ-MnO2 surface, and that the pH is an important controlling factor for the crystalline structures and thermodynamic stabilities. 相似文献