全文获取类型
收费全文 | 5800篇 |
免费 | 698篇 |
国内免费 | 915篇 |
专业分类
安全科学 | 1501篇 |
废物处理 | 471篇 |
环保管理 | 805篇 |
综合类 | 2752篇 |
基础理论 | 463篇 |
环境理论 | 4篇 |
污染及防治 | 516篇 |
评价与监测 | 383篇 |
社会与环境 | 260篇 |
灾害及防治 | 258篇 |
出版年
2024年 | 13篇 |
2023年 | 83篇 |
2022年 | 153篇 |
2021年 | 206篇 |
2020年 | 211篇 |
2019年 | 193篇 |
2018年 | 168篇 |
2017年 | 242篇 |
2016年 | 256篇 |
2015年 | 304篇 |
2014年 | 315篇 |
2013年 | 452篇 |
2012年 | 512篇 |
2011年 | 472篇 |
2010年 | 346篇 |
2009年 | 342篇 |
2008年 | 210篇 |
2007年 | 382篇 |
2006年 | 399篇 |
2005年 | 305篇 |
2004年 | 241篇 |
2003年 | 246篇 |
2002年 | 221篇 |
2001年 | 186篇 |
2000年 | 185篇 |
1999年 | 169篇 |
1998年 | 103篇 |
1997年 | 105篇 |
1996年 | 102篇 |
1995年 | 69篇 |
1994年 | 55篇 |
1993年 | 53篇 |
1992年 | 38篇 |
1991年 | 28篇 |
1990年 | 23篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
排序方式: 共有7413条查询结果,搜索用时 15 毫秒
991.
复合微生物菌剂强化堆肥技术研究 总被引:23,自引:0,他引:23
采用复合微生物菌剂对生活垃圾的接种堆肥技术进行了实验研究。通过测定堆肥过程中反应器出口O2、CO2与H2S气体浓度及对堆肥样品扫描电镜照片分析,比较了3个接种组与1个对照组中堆料中微生物总数变化、种群结构演替及堆肥腐熟速度。试验结果表明,在原料成分为:生活垃圾/成熟堆肥=80/20,有机物约为60%,初始含水率为55%,初始C/N-30时,对于不同接种量的复合微生物接种系统堆料中分别接种0.2%、0.3%、0.5%(质量百分含量),与加入0.3%灭活菌的对照组进行对比实验,接种复合微生物菌剂堆肥系统不仅微生物总数高于对照组,而且其种群结构合理,能明显提高堆肥效率,有效控制臭气的产生,提高堆肥腐熟度。 相似文献
992.
993.
废气治理的低温等离子体-催化协同净化技术 总被引:2,自引:0,他引:2
低温等离子体 催化协同净化技术具有能耗低、投资少、处理效率高、不产生二次污染等显著优点备受人们的关注。从挥发性有机化合物 (VOC)的转化、氮氧化合物的脱除、汽车尾气净化等不同废气治理的角度 ,概括了目前国内外在这方面的研究进展 ,最后提出了该项技术在环境保护领域的应用前景及研究方向 相似文献
994.
Metal complexation by natural ligands is important for metal transport and distribution in surface and ground water. The goal of the work was to study the ligand exchange rate for two important metal ions in natural aquatic systems (Al, Fe) was determined using EDTA and natural organic matter (NOM) of humic type as ligands. After adding EDTA to a solution containing metal-NOM complexes, these complexes dissociated and metal-EDTA complexes were formed. Metal-NOM complexes were separated from metal-EDTA complexes with the help of size-exclusion chromatography and detected by on-line inductively coupled plasma-mass spectrometry (ICP-MS). Injecting the samples into the system over time after addition of EDTA allowed us to measure the rate of the exchange of NOM by EDTA. The experiments could be well described with a first-order rate law assuming that the dissociation of the metal-NOM complexes is the rate-determining step. The exchange rate of Fe was found to be faster than that of Al. This corresponds well with the exchange rate of water molecules from the coordination sphere of the metal ions, which is also faster for Fe than for Al. Furthermore, the UV and the fluorescence signal of the chromatograms were measured. The results indicate that no disaggregation of NOM molecules took place, although about 75-85% of the aggregate-forming metal ions exchanged NOM by EDTA in their coordination sphere. This suggests clearly the fundamental role of NOM in colloidal transport of metals and in their bioavailability. 相似文献
995.
Pesavento M Biesuz R Profumo A Soldi T 《Environmental science and pollution research international》2003,10(5):317-320
SCOPE: The detection and investigation of metal ions bound in strong complexes in natural waters is a difficult task, due to low concentration of the metal ions themselves, and also of the strong ligands, which, moreover, are often not of a well-defined composition. Here, a method is proposed for the investigation of the speciation of metal ions in natural waters. OBJECTIVE AND METHOD: It is based on the sorption of metal ions on strongly sorbing ion exchange resins, i.e. complexing resins. For this reason the method is called Resin Titration. It has been shown in previous investigations that the concentration of metal ion totally sorbed by a particular resin, and its reaction coefficient in the solution phase in the presence of the resin, can be determined from the sorption data using a simple relationship. Here, a data treatment (the Ruzic linearization method) is proposed for also determining the concentration of the ligands responsible for the complex in equilibrium with the resin. RESULTS: The method was applied to data obtained by Resin Titration of a freshwater and a seawater. Copper(II) and aluminium(III) were considered, using Chelex 100 as a titrant, due to its strong sorbing properties towards these metal ions. The results were: the total metal concentration in equilibrium with the resin, the side reaction coefficients, and the concentration of ligands. In all these cases the ligands forming very strong complexes were found to be at concentration lower than that of the metals. CONCLUSION: The Ruzic linearization method allows the determination of the concentration of the ligands forming very strong complexes in equilibrium with Chelex 100. The reaction coefficient was better determined by the calculation method previously proposed for RT. The ligands responsible for the strong complexes were found to be at low concentration, often lower than that of the metal ions considered. The metal in the original sample is partly bound to these ligands, since the complexes are very strong. Only a part of the metal is linked to weaker ligands, or free. 相似文献
996.
997.
炭素焙烧炉沥青烟净化处理 总被引:1,自引:0,他引:1
采用干式静电除尘技术,对炭素焙烧炉排放的含有烟尘、沥青烟的工业废气进行处理,达到既能高效净化有害气体,又能降低资金投入。处理后的各项指标为:烟尘排放浓度=20.0mg/m3,沥青烟排放浓度=14.2mg/m3,苯并(a)芘排放浓度=0.054×10-3mg/m3,所有污染物均达到排放标准。 相似文献
998.
按GB11890—89顶空气相色谱法分析苯系物时,发现重复性和分割水平样品平行性较差,经仔细分析,是由于使用普通玻璃注射器造成的。为避免此类误差,建议顶空气相色谱法分析时,使用带特氟龙顶端推杆的气密性注射器。 相似文献
999.
填埋场沼气发电的温室气体减排效益分析 总被引:2,自引:0,他引:2
填埋场沼气是垃圾卫生填埋场产生的可利用资源.以深圳下坪垃圾填埋场为例,定量分析垃圾填埋气体发电的温室气体减排效益.结果表明,填埋场沼气发电具有很好的经济效益和环境效益,可作为与发达国家进行CDM(清洁发展机制)项目合作的优先技术领域. 相似文献
1000.