全文获取类型
收费全文 | 1084篇 |
免费 | 45篇 |
国内免费 | 347篇 |
专业分类
安全科学 | 62篇 |
废物处理 | 64篇 |
环保管理 | 92篇 |
综合类 | 553篇 |
基础理论 | 195篇 |
污染及防治 | 366篇 |
评价与监测 | 48篇 |
社会与环境 | 32篇 |
灾害及防治 | 64篇 |
出版年
2023年 | 17篇 |
2022年 | 60篇 |
2021年 | 44篇 |
2020年 | 28篇 |
2019年 | 30篇 |
2018年 | 41篇 |
2017年 | 46篇 |
2016年 | 42篇 |
2015年 | 59篇 |
2014年 | 83篇 |
2013年 | 103篇 |
2012年 | 99篇 |
2011年 | 98篇 |
2010年 | 80篇 |
2009年 | 66篇 |
2008年 | 82篇 |
2007年 | 69篇 |
2006年 | 75篇 |
2005年 | 48篇 |
2004年 | 31篇 |
2003年 | 36篇 |
2002年 | 32篇 |
2001年 | 29篇 |
2000年 | 21篇 |
1999年 | 20篇 |
1998年 | 23篇 |
1997年 | 22篇 |
1996年 | 16篇 |
1995年 | 14篇 |
1994年 | 11篇 |
1993年 | 15篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有1476条查询结果,搜索用时 265 毫秒
941.
To study the transport mechanism of hydrophobic organic chemicals (HOCs) and the energy change in soil/solvent system, a soil leaching column chromatographic (SLCC) experiment at an environmental temperature range of 20-40 degrees C was carried out, which utilized a reference soil (SP 14696) packed column and a methanol-water (1:4 by volume ratio) eluent. The transport process quickens with the increase of column temperature. The ratio of retention factors at 30 and 40 degrees C (k'30/k'40) ranged from 1.08 to 1.36. The lower enthalpy change of the solute transfer in SLCC (from eluent to soil) than in conventional reversed-phase liquid chromatography (e.g., from eluent to C18) is consistent with the hypothesis that HOCs were dominantly and physically partitioned between solvent and soil. The results were also verified by the linear solvation energy relationships analysis. The chief factor controlling the retention was found to be the solute solvophobic partition, and the second important factor was the solute hydrogen-bond basicity, while the least important factors were the solute polarizability-dipolarity and hydrogen-bond acidity. With the increase of temperature, the contributions of the solute solvophobic partition and hydrogen-bond basicity gradually decrease, and the latter decreases faster than the former. 相似文献
942.
Implications of rhizospheric heavy metals and nutrients for the growth of alfalfa in sludge amended soil 总被引:3,自引:0,他引:3
Rhizospheric distribution of nutrients and heavy metals in sludge amended soil was investigated using the rhizobag technique to give an indication of the release of metals from wastewater sludge. DTPA-extractable Zn, Cd, Ni and Mn, and available P, K and NH4+-N in the rhizosphere were markedly depleted when soil was amended with sludge. There was no conspicuous depletion or accumulation of DTPA-extractable Cu in the rhizosphere when the soil was amended with sewage sludge but DTPA-extractable Fe accumulated in the rhizosphere when the soil was amended with increasing amounts of sludge. The pH value in the rhizosphere increased with distance from the roots when soil was amended with larger amounts of sludge. The exchangeable fraction of Cu in the rhizosphere was depleted whether or not the soil was treated with sludge. Carbonate, oxide, organic and residual fractions of Cu and Zn were depleted in the rhizosphere at a distance of 0-2 mm from the roots when soil was amended with 50% sludge. Application of sewage sludge had a positive effect on alfalfa growth. With an increase in sludge amounts, the concentrations of Fe, Cu and Zn in alfalfa shoots did not change. Soil amendments with less than 25% sludge did not increase the availability or mobility of heavy metals. The depletion in rhizospheric DTPA-extractable Zn, Cd and Ni indicates that with the sole exception of Cu, release of metals from sludge amended soil was very limited. 相似文献
943.
944.
The purpose of this study is to reveal the role of cupric ions as a natural water contaminant in the H2O2/UV oxidation of humic acids. Humic acids are naturally occurring organic matter and exhibit a strong tendency of complexation with some transition metal ions. Chlorination of humic acids causes potential health hazards due to formation of trihalomethane (THM). The removal of THM precursors has become an issue of public concern. The H2O2/UV process is capable of mineralizing humic acids due to formation of a strong oxidant, hydroxyl radicals, in reaction solution. Experiments were conducted in a re-circulated photoreactor. Different cupric concentrations (0-3.8 mg/l) and different pH values (4-9) were controlled to determine their effects on the degradation of humic acids, UV light absorbance at 254 nm, and H2O2. The presence of cupric ions inhibits humic mineralization and decreases the rate of destruction of humic acids which absorb UV light at 254 nm. On the other hand, the higher the cupric concentration, the lower the H2O2 decomposition rate. In the studied pH range, the minimum of total organic carbon (TOC) removal occurs at pH = 6 in the presence of 2.6 mg/l of cupric ions; both acidification (pH = 4) and alkaline condition (pH = 9) lead to a better removal of TOC. It is inferred from this study that the cupric-complexed form of humic acids is more refractory than the non-complexed one. 相似文献
945.
Kim M Youn SM Shin SH Jang JG Han SH Hyun MS Gadd GM Kim HJ 《Journal of environmental monitoring : JEM》2003,5(4):640-643
A biochemical oxygen demand (BOD) monitoring system, based on electrochemically-active bacteria in combination with a microbial fuel cell, has been developed for the purpose of on-site, on-line and real-time monitoring of practical wastewater. A microbial fuel cell that had been enriched with electrochemically-active bacteria was used as the basis of the measurement system. When synthetic wastewater was fed to the system, the current generation pattern and its Coulombic yield were found to be dependent on the BOD5 of the synthetic wastewater. A linear correlation between the Coulombic yields and the BOD5 of the synthetic wastewater were established. Real wastewater obtained from a sewage treatment plant also produced a highly linear correlation between the Coulombic yield and BOD5 in the system. To examine on-site, on-line and real-time monitoring capability, the BOD monitoring system was installed at a sewage treatment plant. Over 60 days, the measurement system was successfully operated with high accuracy and good stability with the measuring period for a sample being 45 min. This application showed that the application of the measurement system was a rapid and practical way for the determination of BOD5 in water industries. 相似文献
946.
947.
微生物腐蚀造成设备快速破坏,影响系统功能,甚至发生工伤事故,已引起人们的重视。笔者研究了微生物对304L不锈钢焊接缺陷的腐蚀影响。在微生物腐蚀(MIC)的试验的过程中,对试样的开路电势(OCP)进行了测试。结果表明,微生物的存在会促使电势跃迁。当试样发生点蚀时,开路电势又会急剧下降。在一系列的焊接缺陷中,金色的氧化色对微生物腐蚀最敏感。笔者还对点蚀坑上的生物包的形貌、成分及微生物种类进行了分析 相似文献
948.
根据氨溶于水时平衡常数与温度的关系,求出非离子氨摩尔百分比的表达式,接用公式在计算器上编程换算非离子氨浓度,可提高数据的准确性和批量数据处理效率。 相似文献
949.
贵州水城盆地的抽水塌陷研究 总被引:3,自引:2,他引:1
塌陷是岩溶地区的一种主要地质灾害,其成因多种多样,但过量抽取地下水是形成塌陷的主要原因.本文以水城盆地抽水塌陷为例.论述了抽水塌陷发育的分布特征,探讨了抽水塌陷的形成条件和形成机理,并简要地提出了防治对策. 相似文献
950.
东南沿海中生代侵入岩可分为三套,与火山活动有关的第二套,第三套侵入岩在浙东——闽东区有成分上对应的火山岩。下火山岩系和第二套侵入岩是挤压条件下地壳分熔的英安质岩浆经分离结晶形成;上火山岩系和第三套侵入岩是扩张条件上地幔和下地壳分熔形成的双峰式系列,形成高碱流纹岩和碱性花岗岩的A型岩浆地幔物质所占比例最高,由北而南,火山岩覆盖面积渐小,粤东区第二套侵入岩与下火山岩系相比,缺中性岩类,下地壳分熔形成同熔型二长花岗岩及其火山岩,黑云母花岗岩是熔融区上升迁移的结果,第三套侵入岩出露局限。 相似文献