全文获取类型
收费全文 | 10212篇 |
免费 | 1452篇 |
国内免费 | 5560篇 |
专业分类
安全科学 | 1854篇 |
废物处理 | 377篇 |
环保管理 | 946篇 |
综合类 | 9251篇 |
基础理论 | 2028篇 |
环境理论 | 2篇 |
污染及防治 | 1520篇 |
评价与监测 | 660篇 |
社会与环境 | 352篇 |
灾害及防治 | 234篇 |
出版年
2024年 | 33篇 |
2023年 | 429篇 |
2022年 | 602篇 |
2021年 | 669篇 |
2020年 | 663篇 |
2019年 | 691篇 |
2018年 | 546篇 |
2017年 | 508篇 |
2016年 | 616篇 |
2015年 | 693篇 |
2014年 | 625篇 |
2013年 | 1120篇 |
2012年 | 1084篇 |
2011年 | 1168篇 |
2010年 | 775篇 |
2009年 | 908篇 |
2008年 | 761篇 |
2007年 | 875篇 |
2006年 | 868篇 |
2005年 | 628篇 |
2004年 | 533篇 |
2003年 | 442篇 |
2002年 | 325篇 |
2001年 | 282篇 |
2000年 | 251篇 |
1999年 | 195篇 |
1998年 | 152篇 |
1997年 | 151篇 |
1996年 | 119篇 |
1995年 | 114篇 |
1994年 | 74篇 |
1993年 | 75篇 |
1992年 | 46篇 |
1991年 | 21篇 |
1990年 | 23篇 |
1989年 | 20篇 |
1988年 | 14篇 |
1987年 | 6篇 |
1986年 | 11篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 12篇 |
1982年 | 13篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1973年 | 5篇 |
1972年 | 5篇 |
1971年 | 33篇 |
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
991.
通过厌氧折流板反应器(ABR)处理硫酸盐有机废水的实验数据对BP神经网络进行训练,建立了ABR处理硫酸盐有机废水的BPNN模型,通过测试对比,找出了较优训练函数为traingda,较优训练次数为1 900.利用分割连接权值法(PCW)对影响出水SO42-和COD的主要因素进行分析,结果显示进水COD、SO42-、pH、COD/SO42-和HRT对出水SO42-和COD均产生一定影响,其中进水pH对出水SO42-和COD的影响最大,相对重要性(RI)指数分别为30.79%和23.44%;并通过样本试验数据分别建立了对SO42-和COD去除率的限制因子仿真模型,为预测硫酸盐有机废水的厌氧处理过程提供指导. 相似文献
992.
通过A-O工艺对印染废水的降解处理,研究了不同污泥活性下微生物疏水比率和COD去除率的变化规律.结果表明,污泥活性指标ATP浓度与微生物疏水性之间存在一定关系,并对COD去除率产生一定的影响.缺氧污泥的活性指标ATP浓度在0.38~0.77 mg/L范围时,污泥微生物的疏水性最好且疏水比率最高值为84%,COD的去除率最高,为70.01%;好氧污泥的活性指标ATP浓度在0.86~2.17 mg/L范围时,污泥微生物的疏水性最好,疏水比率最高值为75%,COD的去除率最高为96.2%. 相似文献
993.
Akira Sano Makoto KanomataHiroki Inoue Norio SugiuraKai-Qin Xu Yuhei Inamori 《Chemosphere》2012,89(10):1243-1247
The objective of the present study was to establish an alkali extraction technology for FePO4-containing sewage sludge obtained from a wastewater treatment system that includes phosphorous removal by iron electrolysis. By clarifying the extraction properties of phosphorous, organic matter, and inorganic matter, conditions for alkali extraction were optimized. As a result, it was suggested that unheated phosphorous extraction would be superior for FePO4-containing sewage sludge. And, extraction methods and sewage sludge properties were also compared, and the noteworthy result that extraction of metals can be suppressed to extremely low amounts with alkali extraction as compared with acid extraction was obtained. A new insight was also gained that, as compared with the use of incinerated ash reported in previous studies, alkali extraction was more efficient when raw sewage sludge was used. 相似文献
994.
995.
《Journal of environmental science and health. Part. B》2013,48(4):533-549
Abstract The biotransformation of the nonylphenol isomer [ring-U-14C]-4-(3′,5′-dimethyl-3′-heptyl)-phenol (4-353-NP, consisting of two diastereomers) was studied in soybean and Agrostemma githago cell suspension cultures. With the A. githago cells, a batch two-liquid-phase system (medium/n-hexadecane 200:1, v/v) was used, in order to produce higher concentrations and amounts of 4-353-NP metabolites for their identification; 4-353-NP was applied via the n-hexadecane phase. Initial concentrations of [14C]-4-353-NP were 1 mg L?1 (soybean), and 5 and 10 mg L?1 (A. githago). After 2 (soybean) and 7 days (A. githago) of incubation, the applied 4-353-NP was transformed almost completely by both plant species to four types of products: glycosides of parent 4-353-NP, glycosides of primary 4-353-NP metabolites, nonextractable residues and unknown, possibly polymeric materials detected in the media. The latter two products emerged especially in soybean cultures. Portions of primary metabolites amounted to 19–22% (soybean) and 21–42% of applied 14C (A. githago). After liberation from their glycosides, the primary 4-353-NP metabolites formed by A. githago were isolated by HPLC and examined by GC-EIMS as trimethylsilyl derivatives. In the chromatograms, eight peaks were detected which due to their mass spectra, could be traced back to 4-353-NP. Seven of the compounds were side-chain monohydroxylated 4-353-NP metabolites, while the remaining was a (side-chain) carboxylic acid derivative. Unequivocal identification of the sites of hydroxylation/oxidation of all transformation products was not possible. The main primary metabolites produced by A. githago were supposed to be four diastereomers of 6′-hydroxy-4-353-NP (about 80% of all products identified). It was concluded that plants contribute to the environmental degradation of the xenoestrogen nonylphenol; the toxicological properties of side-chain hydroxylated nonylphenols remain to be examined. 相似文献
996.
Several classes of oxidative enzymes have shown promise for efficient removal of endocrine disrupting compounds (EDCs) that are resistant to conventional wastewater treatments. Although the kinetics of reactions between individual EDCs and selected oxidative enzymes are well documented in the literature, there has been little investigation of reactions with EDC mixtures. This makes it impossible to predict how enzyme-mediated treatment systems will perform since wastewater effluents generally contain multiple EDCs. This paper reports pseudo-first order rate constants for a model oxidative enzyme, horseradish peroxidase (HRP), during single-substrate (k1) and mixed-substrate (k1-MIX) reactions. Measured values are compared with literature values of three Michaelis-Menten parameters: half-saturation constant (KM), enzyme turnover number (kCAT), and the ratio kCAT/KM. Published reports had suggested that each of these could be correlated with HRP reactivity towards EDCs in mixtures, and empirical results from this study show that KM can be used to predict the sequence of EDC removal reactions within a particular mixture. We also observed that k1-MIX values were generally greater than k1 values and that compounds exhibiting greatest estrogenic toxicities reacted most rapidly in a given mixture. Finally, because KM may be tedious to measure for every EDC of interest, we have constructed a quantitative structure-activity relationship (QSAR) model to predict these values. This model predicts KM quite accurately (R2 = 89%) based on two molecular characteristics: molecular volume and hydration energy. Its accuracy makes this QSAR a useful tool for predicting which EDCs will be removed most efficiently during enzyme treatment of EDC mixtures. 相似文献
997.
J.D. Nixon D.G. Wright P.K. Dey S.K. Ghosh P.A. Davies 《Waste management (New York, N.Y.)》2013,33(11):2234-2244
The uptake in Europe of Energy from Waste (EfW) incinerator plants has increased rapidly in recent years. In the UK, 25 municipal waste incinerators with energy recovery are now in operation; however, their waste supply chains and business practices vary significantly. With over a hundred more plant developments being considered it is important to establish best business practices for ensuring efficient environmental and operational performance. By reviewing the 25 plants we identify four suitable case study plants to compare technologies (moving grate, fluidised bed and rotary kiln), plant economics and operations. Using data collected from annual reports and through interviews and site visits we provide recommendations for improving the supply chain for waste incinerators and highlight the current issues and challenges faced by the industry. We find that plants using moving grate have a high availability of 87–92%. However, compared to the fluidised bed and rotary kiln, quantities of bottom ash and emissions of hydrogen chloride and carbon monoxide are high. The uptake of integrated recycling practices, combined heat and power, and post incineration non-ferrous metal collections needs to be increased among EfW incinerators in the UK. We conclude that one of the major difficulties encountered by waste facilities is the appropriate selection of technology, capacity, site, waste suppliers and heat consumers. This study will be of particular value to EfW plant developers, government authorities and researchers working within the sector of waste management. 相似文献
998.
《Journal of environmental science and health. Part. B》2013,48(5-6):765-777
Abstract Four methods were developed for the analysis of fluroxypyr in soil samples from oil palm plantations. The first method involved the extraction of the herbicide with 0.05 M NaOH in methanol followed by purification using acid base partition. The concentrated material was subjected to derivatization and then cleaning process using a florisil column and finally analyzed by gas chromatography (GC) equipped with electron capture detector (ECD). By this method, the recovery of fluroxypyr from the spiked soil ranged from 70 to 104% with the minimum detection limit at 5 µg/kg. The second method involved solid liquid extraction of fluroxypyr using a horizontal shaker followed by quantification using high performance liquid chromatography (HPLC) equipped with UV detector. The recovery of fluroxypyr using this method, ranged from 80 to 120% when the soil was spiked with fluroxypyr at 0.1–0.2 µg/g soil. In the third method, the recovery of fluroxypyr was determined by solid liquid extraction using an ultrasonic bath. The recovery of fluroxypyr at spiking levels of 4–50 µg/L ranged from 88 to 98% with relative standard deviations of 3.0–5.8% with a minimum detection limit of 4 µg/kg. In the fourth method, fluroxypyr was extracted using the solid liquid extraction method followed by the cleaning up step with OASIS® HLB (polyvinyl dibenzene). The recovery of fluroxypyr was between 91 and 95% with relative standard deviations of 4.2–6.2%, respectively. The limit of detection in method 4 was further improved to 1 µg/kg. When the weight of soil used was increased 4 fold, the recovery of fluroxypyr at spiking level of 1–50 µg/kg ranged from 82–107% with relative standard deviations of 0.5–4.7%. 相似文献
999.
1000.