全文获取类型
收费全文 | 1093篇 |
免费 | 149篇 |
国内免费 | 571篇 |
专业分类
安全科学 | 148篇 |
废物处理 | 29篇 |
环保管理 | 82篇 |
综合类 | 1002篇 |
基础理论 | 255篇 |
污染及防治 | 127篇 |
评价与监测 | 135篇 |
社会与环境 | 17篇 |
灾害及防治 | 18篇 |
出版年
2024年 | 4篇 |
2023年 | 23篇 |
2022年 | 57篇 |
2021年 | 58篇 |
2020年 | 62篇 |
2019年 | 66篇 |
2018年 | 68篇 |
2017年 | 67篇 |
2016年 | 87篇 |
2015年 | 102篇 |
2014年 | 78篇 |
2013年 | 135篇 |
2012年 | 106篇 |
2011年 | 74篇 |
2010年 | 66篇 |
2009年 | 56篇 |
2008年 | 52篇 |
2007年 | 91篇 |
2006年 | 84篇 |
2005年 | 58篇 |
2004年 | 52篇 |
2003年 | 51篇 |
2002年 | 42篇 |
2001年 | 42篇 |
2000年 | 30篇 |
1999年 | 27篇 |
1998年 | 36篇 |
1997年 | 22篇 |
1996年 | 23篇 |
1995年 | 14篇 |
1994年 | 15篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1972年 | 3篇 |
1971年 | 1篇 |
排序方式: 共有1813条查询结果,搜索用时 31 毫秒
761.
762.
用普通活性污泥经120d富集,得到氨氧化菌混培物,氨氧化菌浓度提高300倍.在NO2/O2混合气氛下进行氨氧化试验,结果表明,无分子氧时,氨氧化菌能以NO2为电子受体氧化氨,并产生NO;加入氧气后,氨氧化速率明显提高,最高速率[33(mol NH4 -N/(g MLSS(h)]发生在混合气体中NO2和O2浓度分别为1.79(mol/L和9.38mmol/L时;在NO2浓度为0.89~1.79(mol/L范围内,O2能够强化基于NO2的氨氧化反应,当NO2浓度增大至6.71(mol/L时,氨氧化速率却降低.部分NO被O2氧化,使得反应器出口气体中NO2浓度高于进口.试验过程中产生约20%氮损失,这与氨氧化和厌氧氨氧化相互耦合产生气态含氮产物(N2、NO、N2O)有关. 相似文献
763.
用石墨炉原子吸收分光光度法对水中痕量铜、铅、镉样品进行测定。结果表明,采用合适的仪器和石墨管升温程序条件,并注意进样针位置调节和石墨管的选择,测定的精密度和准确度好,灵敏度高,能满足水中痕量样品的分析。 相似文献
764.
泥炭树脂颗粒对水溶液中十二烷基苯磺酸钠的去除 总被引:1,自引:0,他引:1
泥炭树脂颗粒对水溶液中十二烷基苯磺酸钠 (SDBS)具有很好的去除效果。数据分析表明 ,Freundlich和 Langmuir吸附等温方程可以很好地描述这一过程。通过 L angmuir方程计算出颗粒对 SDBS的最大吸附量为 3 3 .3 3 mg·g- 1。在试验条件下 ,吸附量随着 SDBS的初始浓度增加而增加 ,当溶液的初始 p H在 4~ 8的范围时 ,颗粒对 SDBS吸附量变化很小。溶液的初始浓度对吸附速率产生明显影响 ,浓度越低吸附速率越快 ,达到吸附平衡所需的时间越短。准二级动力学模型能够很好地描述颗粒对 SDBS的吸附过程。 相似文献
765.
Organic compounds in the flue gas from a power station with circulating fluid bed combustion of coal
Numerous organic compounds have been analyzed by coupled gas chromatography-mass spectroscopy (GC-MS) in flue gas after fluid bed combustion of four coal species from South Africa, Poland, Spitsbergen and Ruhr area (Germany). Polynuclear aromatic hydrocarbons, aliphatic hydrocarbons, chlorinated, heterocyclic and nitro compounds as well as phthalate esters are detected. 相似文献
766.
大气微生物粒子与飘尘粒子的关系 总被引:1,自引:0,他引:1
用ANDERSEN生物粒子采样器和光散射气溶胶粒子计数器,在北京西单对大气细菌、真菌和飘尘粒子的浓度、粒度分布及它们之间的关系进行了观测和研究。结果表明,大气细菌的粒度是负偏态分布,大气真菌是对数正态分布,飘尘是正偏态分布。大气细菌浓度与飘尘浓度的比值冬季大,为119538;夏季小,为24217;年平均比值为67517,>2.0μm的菌尘比值为1525387,2.0μm~8.2μm的菌尘比值为3318,>8.2μm的菌尘比值为394。大气真菌浓度与飘尘浓度的比值冬季大,为212770;夏季小,为65585;年平均比值为135344,<2.0μm的菌尘比值为952698,2.0μm~8.2μm的菌尘比值为5343,>8.2μm的菌尘比值为2632。 相似文献
767.
We study how the combination of tides and freshwater buoyancy affects the marine organisms accumulation and horizontal transport
in the ROFI system of the eastern English Channel. The Princeton Ocean Model coupled with a particle-tracking module is used
to study the migration of fish eggs and larvae under different forcing conditions. Results of modeling are validated against
observed concentrations of Flounder (Pleuronectes flesus) larvae. Numerical Lagrangian tracking experiments are performed with passive and active particles, representing sea-water
organisms. Passive particles are neutrally buoyant whereas active particles are able to exercise light dependent vertical
migrations equating to the swimming behavior of larvae. The experiments reveal that the strongest accumulation of particles
occurs along the French coast on the margin of the ROFI. This happens because the interaction between the turbulence, the
freshwater buoyancy input, and tidal dynamics, produces particle trapping and vertical spreading within the frontal convergence
zone. Tides and freshwater input induce net alongshore horizontal transport toward the North. Tidal currents modulate the
magnitude of horizontal transport whereas the fresh water input controls more the location of accumulation zones. Tracking
experiments with active particles indicate that the vertical migration leads to a significant departure from the passive particle
transport pattern. Differences lie in the shape of the particle transport pattern and the rate of the northward migration.
In particular, vertically migrating particles travel slower. To find possible Flounder migration pathways, particles are released
within the assumed spawning area of Flounder. The model predicts larvae drift routes and demonstrates that throughout the
entire particle-tracking period the horizontal structure of the particle distribution is consistent with the larvae concentrations
observed during the field experiments. 相似文献
768.
Site-Specific Characterization of Castromil Brownfield Area Related to Gold Mining Activities 总被引:1,自引:0,他引:1
Ferreira da Silva E Serrano Pinto L Patinha C Cardoso Fonseca E 《Environmental geochemistry and health》2004,26(1):13-25
Castromil is one of the gold mining areas in Portugal that has been abandoned since 1940. This area, which was first mined in Roman times, is located within a Hercynian granite body near the contact with Silurian metasediments. Gold is essentially disseminated along veins in the silicified granite, running NW-SE, related with a shear zone and frequently associated with sulphides (arsenopyrite and basically pyrite). In paragenetic terms, three stages of mineralization are considered: ferro-arseniferous (quartz + arsenopyrite I + pyrite I + pyrrhotite + bismuth), zinciferous (sphalerite + chalcopyrite), and remobilization (arsenopyrite II + galena + gold). Due to the lack of laws and environmental education, Castromil is today a gold mining heritage site where we can detect the consequences of an incautious exploration (tailings, wells and adits located in the old explored zone) and where a residential area is located. In order to characterize the actual state of the old mining area the trace metal contamination of soils and waters by mining activities was investigated. In the studied area 106 soil samples, 15 waters and 20 plants were sampled and analysed. The soil samples were analysed for 32 elements by ICP-AES. Waters were analysed by ionic chromatography and ICP-MS for major and trace elements. Plants were analysed for As, Fe and Pb by AAS. The results are discussed taking into account the risk-based standards for soils and groundwater's (target and intervention values) proposed by Swartjes (1999). The results show elevated concentration of As and Pb which were found in soils collected from agricultural areas. Foodstuff plants species collected in the Castromil agricultural area show high concentrations of As in the leaves (cabbage and lettuce) and in the tubers (potatoes). Groundwaters in the mining area contain high concentrations of As that exceeds the intervention values. The area must to be subject to a remediation process, considering the actual risks to humans and ecosystems and the risks due to contaminant migration. 相似文献
769.
近海海洋大气颗粒物中元素浓度及粒径分布研究 总被引:6,自引:0,他引:6
本工作用质子激发X荧光分析光测定近中国海域上空不同粒径大气颗粒物中14个元素的浓度、粒径分布及富集因子。研究发现,在开阔海域大气污染元素和地壳元素主要来自亚洲大陆长距离输送的贡献,海水元素浓度受海盐气溶胶的控制,估算近中国海域大气中的尘土量为0.4-2.3μg/m^3,尘土粒子的输入量控制着海洋大气颗粒物中地壳元素浓度。 相似文献
770.
B. E. Davies Claudio Bifano K. M. Phillips J. L. Mogollon M. Torres 《Environmental geochemistry and health》1999,21(3):227-256
Surface soils (0–15 cm) were sampled at 10–20 km intervals along two transects in Venezuela. One (1162 km, 70 samples) ran west to east parallel with the Caribbean coastline, the other (920 km, 92 samples) ran south to north from the frontier with Brazil to the Caribbean shore. Sampling took place in both a wet and a dry season. Trace metals were extracted from dried, sieved (<2 mm) soil with boiling aqua regia followed by analysis by ICP or flame AAS. Metal values did not differ significantly between the two seasons and dates were averaged. Geometric mean values for the west–east transect were: Cr=41.5, Cu 17.9, Cs 3.6, Li=13.9, Mn=294, Ni=21.3, Pb=17.4, Sr=39.4, V=60.4 and Zn = 83.7g g–1, respectively. Similarly, for the south–north transect Cr=21.3, Cu=4.3, Cs=1.1, Li=2.0, Mn=55.7, Ni=4.4, Pb=6.1, Sr=13.3, V=28.2 and Zn=16.7g g–1, respectively. A classification of samples by lithology showed surface soil composition to be related to rock composition. Metal values were low in the soils in the south of the country, in the Guyana highlands (Gran Sabana). Low Zn contents were prevalent. Lead contents were affected by roadside fallout from vehicles using leaded petrol except that high Pb contents of soils in the Gran Sabana were of more complex origin. 相似文献