全文获取类型
收费全文 | 1056篇 |
免费 | 42篇 |
国内免费 | 80篇 |
专业分类
安全科学 | 67篇 |
废物处理 | 32篇 |
环保管理 | 104篇 |
综合类 | 308篇 |
基础理论 | 280篇 |
环境理论 | 1篇 |
污染及防治 | 232篇 |
评价与监测 | 73篇 |
社会与环境 | 56篇 |
灾害及防治 | 25篇 |
出版年
2023年 | 17篇 |
2022年 | 21篇 |
2021年 | 26篇 |
2020年 | 21篇 |
2019年 | 22篇 |
2018年 | 24篇 |
2017年 | 38篇 |
2016年 | 40篇 |
2015年 | 30篇 |
2014年 | 32篇 |
2013年 | 62篇 |
2012年 | 51篇 |
2011年 | 65篇 |
2010年 | 45篇 |
2009年 | 49篇 |
2008年 | 68篇 |
2007年 | 65篇 |
2006年 | 52篇 |
2005年 | 31篇 |
2004年 | 35篇 |
2003年 | 45篇 |
2002年 | 38篇 |
2001年 | 26篇 |
2000年 | 31篇 |
1999年 | 13篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 14篇 |
1994年 | 9篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 14篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 17篇 |
1978年 | 9篇 |
1977年 | 13篇 |
1976年 | 12篇 |
1975年 | 9篇 |
1974年 | 3篇 |
排序方式: 共有1178条查询结果,搜索用时 0 毫秒
131.
在CO2吸收过程中,选择具有不挥发和不发生氧化降解特性的氨基酸盐吸收剂有助于降低吸收剂损失和减轻环境污染风险,故本研究以CO2吸收速率和再生速率为指标,对L-精氨酸和精氨酸钾(PA)吸收剂的CO2吸收性能和常压下热再生性能进行了实验分析,并研究了吸收剂质量分数、反应温度及吸收-再生循环次数对CO2吸收特性的影响,同时还与乙醇胺(MEA)、二乙醇胺(DEA)和三乙醇胺(TEA)进行了对比分析.结果表明,在实验的质量分数范围内,PA具有最高的CO2吸收速率和吸收能力,分别为24.5×10-3mol.(L.min)-1和1.99 mol.mol-1,比相同质量分数的MEA高2.1%和290.2%.温度影响结果表明,40℃时PA和MEA的CO2吸收速率均高于其他实验温度.相同再生条件下,PA的贫液CO2负荷要略高于MEA,但PA的再生程度可达72.8%,比MEA高19%.同时,3次"吸收-再生"循环之后,10%PA的CO2吸收能力仍可保持在1.03mol.mol-1,比10%MEA高255.2%.实验结果也表明,L-精氨酸具有较强的CO2吸收能力,其CO2吸收速率与同质量分数的DEA可比. 相似文献
132.
133.
134.
C. Barker Jørgensen 《Marine Biology》1981,65(2):159-163
Feeding and pseudofeces formation were studied in intact Mytilus edulis clearing suspensions of graphite particles, and the processes were compared with activities observed in mussels with a severed adductor muscle. Most particulate material in the stomach was present in the suspended state. Ingestion of particles in suspension could take place concurrently with the production of pseudofeces. Severing of the adductor muscle resulted in profuse secretion of mucus that gradually subsided to a constant low level. Addition of graphite particles at concentrations that did not cause mucus secretion in the intact mussels strongly stimulated secretion in the operated mussels, resulting in the accumulation of highly viscid, mucusparticle aggregates. These aggregates were mechanically stable, in contrast to the fragile pseudofeces. It is indicated that normal feeding depends upon hydromechanical mechanisms that produce highly concentrated suspensions of particles for ingestion, and that mucociliary mechanisms serve to clean the gills and other organs of the mantle cavity for excess particulate material. It is further indicated that intact mussels secrete mucus only in the amounts needed to consolidate excess particulate material, and that lesions affect the normal balance between particles in suspension and mucus secretion by enhancing the sensitivity of the mechanisms that control mucus secretion. 相似文献
135.
136.
137.
Cox G Beresford NA Alvarez-Farizo B Oughton D Kis Z Eged K Thørring H Hunt J Wright S Barnett CL Gil JM Howard BJ Crout NM 《Journal of environmental radioactivity》2005,83(3):383-397
A spatially implemented model designed to assist the identification of optimal countermeasure strategies for radioactively contaminated regions is described. Collective and individual ingestion doses for people within the affected area are estimated together with collective exported ingestion dose. A range of countermeasures are incorporated within the model, and environmental restrictions have been included as appropriate. The model evaluates the effectiveness of a given combination of countermeasures through a cost function which balances the benefit obtained through the reduction in dose with the cost of implementation. The optimal countermeasure strategy is the combination of individual countermeasures (and when and where they are implemented) which gives the lowest value of the cost function. The model outputs should not be considered as definitive solutions, rather as interactive inputs to the decision making process. As a demonstration the model has been applied to a hypothetical scenario in Cumbria (UK). This scenario considered a published nuclear power plant accident scenario with a total deposition of 1.7x10(14), 1.2x10(13), 2.8x10(10) and 5.3x10(9)Bq for Cs-137, Sr-90, Pu-239/240 and Am-241, respectively. The model predicts that if no remediation measures were implemented the resulting collective dose would be approximately 36 000 person-Sv (predominantly from 137Cs) over a 10-year period post-deposition. The optimal countermeasure strategy is predicted to avert approximately 33 000 person-Sv at a cost of approximately 160 million pounds. The optimal strategy comprises a mixture of ploughing, AFCF (ammonium-ferric hexacyano-ferrate) administration, potassium fertiliser application, clean feeding of livestock and food restrictions. The model recommends specific areas within the contaminated area and time periods where these measures should be implemented. 相似文献
138.
The one-dimensional pesticide fate model MACRO was loose-linked to the three-dimensional discrete fracture/matrix diffusion model FRAC3DVS to describe transport of the pesticide mecoprop in a fractured moraine till and local sand aquifer (5-5.5 m depth) overlying a regional limestone aquifer (16 m depth) at Havdrup, Denmark. Alternative approaches to describe the upper boundary in the groundwater model were examined. Field-scale simulations were run to compare a uniform upper boundary condition with a spatially variable upper boundary derived from Monte-Carlo simulations with MACRO. Plot-scale simulations were run to investigate the influence of the temporal resolution of the upper boundary conditions for fluxes in the groundwater model and the effects of different assumptions concerning the macropore/fracture connectivity between the two models. The influence of within-field variability of leaching on simulated mecoprop concentrations in the local aquifer was relatively small. A fully transient simulation with FRAC3DVS gave 20 times larger leaching to the regional aquifer compared to the case with steady-state water flow, assuming full connectivity with respect to macropores/fractures across the boundary between the two models. For fully transient simulations 'disconnecting' the macropores/fractures at the interface between the two models reduced leaching by a factor 24. A fully connected, transient simulation with FRAC3DVS, with spatially uniform upper boundary fluxes derived from a MACRO simulation with 'effective' parameters is therefore recommended for assessing leaching risks to the regional aquifer, at this, and similar sites. 相似文献
139.
A previous model of the global heat balance has been expanded by including the influence of SO2 pollution, water content of the atmosphere and cloudiness. It was found that the previous results were not changed significantly by this expansion of the model. The conclusions set up uising the previous model were still valid: (1) it is great importance to include the buffer capacity of the sea, including its dependence on pH and the temperature; (2) it is of importance to include natural climatic variations; (3) the dominanting factor is the trend in the consumption of fossil fuel. 相似文献
140.
Løkke S 《Environmental science and pollution research international》2006,13(5):342-349