全文获取类型
收费全文 | 14607篇 |
免费 | 766篇 |
国内免费 | 5436篇 |
专业分类
安全科学 | 1057篇 |
废物处理 | 860篇 |
环保管理 | 1106篇 |
综合类 | 8764篇 |
基础理论 | 2436篇 |
环境理论 | 6篇 |
污染及防治 | 4730篇 |
评价与监测 | 618篇 |
社会与环境 | 609篇 |
灾害及防治 | 623篇 |
出版年
2024年 | 11篇 |
2023年 | 254篇 |
2022年 | 698篇 |
2021年 | 626篇 |
2020年 | 510篇 |
2019年 | 468篇 |
2018年 | 593篇 |
2017年 | 704篇 |
2016年 | 648篇 |
2015年 | 861篇 |
2014年 | 1111篇 |
2013年 | 1497篇 |
2012年 | 1245篇 |
2011年 | 1424篇 |
2010年 | 1038篇 |
2009年 | 1040篇 |
2008年 | 1073篇 |
2007年 | 916篇 |
2006年 | 835篇 |
2005年 | 585篇 |
2004年 | 447篇 |
2003年 | 519篇 |
2002年 | 453篇 |
2001年 | 363篇 |
2000年 | 389篇 |
1999年 | 428篇 |
1998年 | 345篇 |
1997年 | 331篇 |
1996年 | 307篇 |
1995年 | 271篇 |
1994年 | 188篇 |
1993年 | 166篇 |
1992年 | 116篇 |
1991年 | 96篇 |
1990年 | 65篇 |
1989年 | 55篇 |
1988年 | 44篇 |
1987年 | 21篇 |
1986年 | 22篇 |
1985年 | 11篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Qiuyi Ji Huan He Zhanqi Gao Xiaohan Wang Shaogui Yang Cheng Sun Shiyin Li Yong Wang Limin Zhang 《环境科学学报(英文版)》2020,32(12):55-61
Tri(2-chloroethyl) phosphate (TCEP) with the initial concentration of 5 mg/L was degraded by UV/H2O2 oxidation process. The removal rate of TCEP in the UV/H2O2 system was 89.1% with the production of Cl? and PO43? of 0.23 and 0.64 mg/L. The removal rate of total organic carbon of the reaction was 48.8% and the pH reached 3.3 after the reaction. The oxidative degradation process of TCEP in the UV/H2O2 system obeyed the first order kinetic reaction with the apparent rate constant of 0.0025 min?1 (R2=0.9788). The intermediate products were isolated and identified by gas chromatography-mass spectrometer. The addition reaction of HO? and H2O and the oxidation reaction with H2O2 were found during the degradation pathway of 5 mg/L TCEP in the UV/H2O2 system. For the first time, environment risk was estimated via the “ecological structure activity relationships” program and acute and chronic toxicity changes of intermediate products were pointed out. The luminescence inhibition rate of photobacterium was used to evaluate the acute toxicity of intermediate products. The results showed that the toxicity of the intermediate products increased with the increase of reaction time, which may be due to the production of chlorine compounds. Some measures should be introduced to the UV/H2O2 system to remove the highly toxic Cl-containing compounds, such as a nanofiltration or reverse osmosis unit. 相似文献
32.
Da Zhang Jingfeng Gao Lifang Zhang Wenzhi Zhang Jingxin Ji Huihui Dai Zhiqi Wang 《环境科学学报(英文版)》2020,32(6):211-223
Triclosan(TCS) is commonly found in wastewater treatment plants,which often affects biological treatment processes.The responses of nitrification,antibiotic resistome and microbial community under different TCS concentrations in activated sludge system were evaluated in this study.The experiment was conducted in a sequencing batch reactor(SBR)for 240 days.Quantitative PCR results demonstrated that the abundance of ammonium oxidizing bacteria could be temporarily inhibited by 1 mg/L TCS and then gradually recovered.And the abundances of nitrite oxidizing bacteria(NOB) under 2.5 and 4 mg/L TCS were three orders of magnitude lower than that of seed sludge,which accounted for partial nitrification.When the addition of TCS was stopped,the abundance of NOB increased.The mass balance experiments of TCS demonstrated that the primary removal pathway of TCS changed from adsorption to biodegradation as TCS was continuously added into the SBR system.Moreover,TCS increased the abundance of mexB,indicating the efflux pump might be the main TCS-resistance mechanism.As a response to TCS,bacteria could secrete more protein(PN) than polysaccharide.Three-dimensional excitation-emission matrix revealed that tryptophan PN-like substances might be the main component in PN to resist TCS.High-throughput sequencing found that the relative abundances of Paracoccus,Pseudoxanthomonas and Thauera increased,which could secrete extracellular polymeric substances(EPS).And Sphingopyxis might be the main TCS-degrading bacteria.Overall,TCS could cause partial nitrification and increase the relative abundances of EPS-secreting bacteria and TCS-degrading bacteria. 相似文献
33.
Ozone pollution characteristics and sensitivity analysis using an observation-based model in Nanjing, Yangtze River Delta Region of China 总被引:1,自引:0,他引:1
Ming Wang Wentai Chen Lin Zhang Wei Qin Yong Zhang Xiangzhi Zhang Xin Xie 《环境科学学报(英文版)》2020,32(7):13-22
Ground-level ozone (O3) has become a critical pollutant impeding air quality improvement in Yangtze River Delta region of China. In this study, we present O3 pollution characteristics based on one-year online measurements during 2016 at an urban site in Nanjing, Jiangsu Province. Then, the sensitivity of O3 to its precursors during 2 O3 pollution episodes in August was analyzed using a box model based on observation (OBM). The relative incremental reactivity (RIR) of hydrocarbons was larger than other precursors, suggesting that hydrocarbons played the dominant role in O3 formation. The RIR values for NOX ranged from –0.41%/% to 0.19%/%. The O3 sensitivity was also analyzed based on relationship of simulated O3 production rates with reductions of VOC and NOX derived from scenario analyses. Simulation results illustrate that O3 formation was between VOCs-limited and transition regime. Xylenes and light alkenes were found to be key species in O3 formation according to RIR values, and their sources were determined using the Positive Matrix Factorization (PMF) model. Paints and solvent use was the largest contributor to xylenes (54%), while petrochemical industry was the most important source to propene (82%). Discussions on VOCs and NOX reduction schemes suggest that the 5% O3 control goal can be achieved by reducing VOCs by 20%. To obtain 10% O3 control goal, VOCs need to be reduced by 30% with VOCs/NOX larger than 3:1. 相似文献
34.
Yi Shi Akintunde Babatunde Bettina Bockelmann-Evans Qijie Li Liang Zhang 《环境科学学报(英文版)》2020,32(10):151-162
Within the drinking water distribution system (DWDS) using chloramine as disinfectant, nitrification caused by nitrifying bacteria is increasingly becoming a concern as it poses a great challenge for maintaining water quality. To investigate efficient control strategies, operational conditions including hydraulic regimes and disinfectant scenarios were controlled within a flow cell experimental facility. Two test phases were conducted to investigate the effects on the extent of nitrification of three flow rates (Q = 2, 6, and 10 L/min) and four disinfection scenarios (total Cl2=1 mg/L, Cl2/NH3-N=3:1; total Cl2=1 mg/L, Cl2/NH3-N=5:1; total Cl2=5 mg/L, Cl2/NH3-N=3:1; and total Cl2=5 mg/L, Cl2/NH3-N=5:1). Physico-chemical parameters and nitrification indicators were monitored during the tests. The characteristics of biofilm extracellular polymetric substance (EPS) were evaluated after the experiment. The main results from the study indicate that nitrification is affected by hydraulic conditions and the process tends to be severe when the fluid flow transforms from laminar to turbulent (2300<Re<4000). Increasing disinfectant concentration and optimizing Cl2/NH3-N mass ratio were found to inhibit nitrification to some extend when the system was running at turbulent condition (Q = 10 L/min, Re = 5535). EPS extracted from biofilm that was established at the flow rate of 6 L/min had greater carbohydrate/protein ratio. Furthermore, several nitrification indicators were evaluated for their prediction efficiency and the results suggest that the change of nitrite, together with total organic carbon (TOC) and turbidity can indicate nitrification potential efficiently. 相似文献
35.
Mengwei Zhang Wanyue Liu Qian Qu Mingjing Ke Zhenyan Zhang Zhigao Zhou Tao Lu Haifeng Qian 《环境科学学报(英文版)》2020,32(11):102-109
An effective broad-spectrum fungicide, azoxystrobin (AZ), has been widely detected in aquatic ecosystems, potentially affecting the growth of aquatic microorganisms. In the present study, the eukaryotic alga Monoraphidium sp. and the cyanobacterium Pseudanabaena sp. were exposed to AZ for 7 days. Our results showed that 0.2–0.5 mg/L concentrations of AZ slightly inhibited the growth of Monoraphidium sp. but stimulated Pseudanabaena sp. growth. Meanwhile, AZ treatment effectively increased the secretion of total organic carbon (TOC) in the culture media of the two species, and this phenomenon was also found in a freshwater microcosm experiment (containing the natural microbial community). We attempted to assess the effect of AZ on the function of aquatic microbial communities through metabolomic analysis and further explore the potential risks of this compound. The metabonomic profiles of the microcosm indicated that the most varied metabolites after AZ treatment were related to the citrate cycle (TCA), fatty acid biosynthesis and purine metabolism. We thereby inferred that the microbial community increased extracellular secretions by adjusting metabolic pathways, which might be a stress response to reduce AZ toxicity. Our results provide an important theoretical basis for further study of fungicide stress responses in aquatic microcosm microbial communities, as well as a good start for further explorations of AZ detoxification mechanisms, which will be valuable for the evaluation of AZ environmental risk. 相似文献
36.
分别采用单因子评价法、综合污染指数评价法和模糊综合评价法对2015—2018年河南省辖海河流域的水质改善效果进行评价分析。结果表明:3种方法的评价结果基本一致,2015—2018年河南省辖海河流域整体水质呈现改善趋势。但各方法侧重点有所不同。单因子评价结果显示,海河流域21项污染因子Ⅰ—Ⅲ类数量占比由2015年的69.63%增加至2018年的89.52%,劣Ⅴ类占比由2015年的15.13%减少至2018年的0.85%;海河流域综合污染指数由2015年的0.89降低至2018年的0.56,水质级别由中度污染改善为轻度污染,其中卫河、共产主义渠、大沙河、安阳河、汤河、马颊河的水质状况均有一定改善;模糊评价结果显示,NH3-N和TP在9项评价因子中权重占比较大,是河南省辖海河流域的主要污染因子;2018年8条河流均达到Ⅰ—Ⅲ类水质。前2种评价方法适用于管理分析,模糊评价法可补充说明河流存在的问题,更适用于研究工作。 相似文献
37.
38.
为解决重金属污染土在电动法修复过程中存在的聚焦效应问题,提出了牺牲铁阳极的电化学联用修复技术。在传统电动修复方法基础上增加电解液净化循环装置,优化Cr(Ⅵ)还原及沉淀所需技术参数,并与传统电动修复技术进行对比,探讨其修复效果及适用性。结果表明:迁出的Cr(Ⅵ)可在Fe2+作用下被还原为Cr(Ⅲ)并沉淀,pH、电压梯度、电流密度、电极面积均会影响其反应速率,电极距离对反应速率无直接影响,主要影响电解功率。Cr(Ⅵ)还原-沉淀反应的最佳技术参数为:pH值5~6.5,电压梯度0.8 V/cm,电流密度>6.67 mA/cm2,电极面积90 cm2,电极距离15 cm;较传统电动修复技术,以牺牲阳极强化铬污染土的电化学联用修复技术中,土壤室不同点位的去除率波动范围在10%,最高点位的去除率提高近24%,达93.4%。靠近阳极附近土体中Cr(Ⅵ)去除率从0.24%提高到80.38%。以牺牲阳极强化污染土的电化学联用修复方法不仅有效解决了重金属迁移的聚焦问题,而且有助于促进土中重金属污染物的整体性迁出。 相似文献
39.
以餐饮废油制备生物柴油的副产物粗甘油为碳源,采用圆红冬孢酵母发酵生产微生物油脂。通过对发酵影响因素的优化,确定了最适发酵条件为:种子复苏时长24 h、富集时长10 h、接种量为6%、初始粗甘油浓度为60 g/L、C/N为60、有机氮占总氮比例为75%、发酵体积为100 mL、发酵温度为30 ℃、发酵时间为6 d,在此条件下,获得总产油量为10.56 g/L,油脂产率为0.229。与无机氮源硫酸铵相比,有机氮源蛋白胨的添加显著提高了油脂含量和总产油量。通过测定油脂的脂肪酸成分并利用Hoekman方程估算所得生物柴油的性能指标,表明其符合中国、美国及欧盟标准。该方法既为粗甘油的再利用提供了一条新途径,又为生物柴油的生产提供了廉价的原材料。 相似文献
40.
目的研究舰载机机载装备弹射起飞和拦阻着陆冲击试验的工程实现方法。方法从GJB 150.18A—2009、MIL-STD-810F/G及其提供的实测数据出发,分析弹射起飞和拦阻着陆冲击载荷特征,对几种常用试验方法的工程实现进行探讨和比较。结果弹射起飞和拦阻着陆冲击具有瞬态、交变、低频、大位移、高速度等特征。阻尼正弦波方法的实施路径比较明确,复杂波形再现方法实施路径比较模糊且复杂,超长脉冲半正弦波方法具有多种局限性,前两种方法的速度、位移都较大。结论阻尼正弦波方法较复杂波形再现方法更容易实现,但两者都需要大位移、高速度的专用冲击试验设备和适当的波形处理技术,超长脉冲半正弦波方法在前面两种标准推荐方法能够实现时,不建议使用。 相似文献