全文获取类型
收费全文 | 5320篇 |
免费 | 624篇 |
国内免费 | 923篇 |
专业分类
安全科学 | 1026篇 |
废物处理 | 199篇 |
环保管理 | 644篇 |
综合类 | 3116篇 |
基础理论 | 469篇 |
环境理论 | 1篇 |
污染及防治 | 406篇 |
评价与监测 | 529篇 |
社会与环境 | 197篇 |
灾害及防治 | 280篇 |
出版年
2024年 | 15篇 |
2023年 | 86篇 |
2022年 | 175篇 |
2021年 | 241篇 |
2020年 | 188篇 |
2019年 | 165篇 |
2018年 | 175篇 |
2017年 | 216篇 |
2016年 | 257篇 |
2015年 | 289篇 |
2014年 | 309篇 |
2013年 | 378篇 |
2012年 | 493篇 |
2011年 | 477篇 |
2010年 | 329篇 |
2009年 | 317篇 |
2008年 | 230篇 |
2007年 | 383篇 |
2006年 | 341篇 |
2005年 | 300篇 |
2004年 | 226篇 |
2003年 | 217篇 |
2002年 | 167篇 |
2001年 | 144篇 |
2000年 | 119篇 |
1999年 | 114篇 |
1998年 | 108篇 |
1997年 | 115篇 |
1996年 | 66篇 |
1995年 | 45篇 |
1994年 | 41篇 |
1993年 | 36篇 |
1992年 | 21篇 |
1991年 | 19篇 |
1990年 | 12篇 |
1989年 | 11篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1980年 | 4篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 4篇 |
1972年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有6867条查询结果,搜索用时 15 毫秒
921.
922.
武汉市某区域大气颗粒物的测定与分析 总被引:4,自引:0,他引:4
采用电感耦合等离子体原子发射光谱法对TSP环境样品和尘源样品中的S、Si、Ti、Al、As、Ca、Pb、V等30余个元素组份进行分析并计算出各元素的含量,得到本区域大气环境TSP和污染尘源元素特征谱,并通过比较微波消解与加热消解两种方法的优劣,确定出较适应消解方法.结果表明,该区域中的A区污染源主要来自道路交通尘源和土壤尘源,B区污染源来自土壤尘源和建筑尘源. 相似文献
923.
张国晖 《安全.健康和环境》2005,5(9):13-15
运用毒害区计算方法对本部贮存的氯气泄漏后扩散的半径进行估算,同时以扩散的半径作参考,提出氯气泄漏的处置方法. 相似文献
924.
建立了一种适用于再生水中优先控制有毒有机污染物筛查的方法.针对样品前处理方法中的固相萃取柱的选择和洗脱剂条件等进行了优化设计,利用保留时间锁定和谱图解卷积技术分辨复杂系统中的目标污染物,并利用有毒化合物数据库进行有毒污染物甄别.结果表明,采用C18柱串联HLB柱的方法进行富集,用1:1(V/V)的正己烷/二氯甲烷混合溶剂和4:1(V/V)的二氯甲烷/甲醇混合溶剂进行分级洗脱的前处理方法,对分配系数(logKow)在1.48~6.41之间的30种化合物平均回收率在52.1%~138%之间,相对标准偏差值均<13.6%.将该方法应用于天津空港地区再生水中有毒有机污染物的筛查,2007~2008年度2次采集样品分别筛查出30种有毒有机污染物,其中有7种属于《城镇污水处理厂污染物排放标准》中已列入监管范围的污染物,11种未列入排放标准监测范围.比较污水处理厂进、出水以及地表水中检出污染物,发现现有污水处理工艺对筛查出的优先有机污染物处理效果不佳. 相似文献
925.
Pooja Suman 《毒物与环境化学》2013,95(10):1880-1896
Validation of method was performed for various pesticides on mango matrix involving the processing of sample at ambient and cryogenic conditions. The linearity, limits of detection, repeatability, matrix effect, and recovery were studied as the aspects of method validation. The effect of matrix on recovery was found to be medium (20–50%) and strong (>50%). After correction by matrix-matched calibration curves, the recovery was calculated to be in the range of 80–107% and 80–105% at ambient and cryogenic processing, respectively. The precision estimated for the recovery of pesticides obtained from both solvent- and matrix-matched calibration curves and at both the processing conditions was determined to be >20% except for chlorpyrifos and atrazine. The uncertainty established for the methodology was >20%, which substantiates the efficiency and reliability of methodology used for pesticide residue analysis in mango in this study. 相似文献
926.
The production of neem oil coated urea (NOCU), a technology developed by the Indian Agricultural Research Institute, has been grown to over 2.0 million tons per year. The estimation of neem oil content in NOCU is important due to its significance in ensuring agronomic efficiency. Therefore, this study was taken up to develop a simple method for the determination of neem oil in NOCU. The procedure involves extraction of neem oil from NOCU; saponification of extracted oil; oxidation of released glycerol to formaldehyde, and subsequent conversion of formaldehyde to a dihydrolutidine derivative. Its concentration was determined spectrophotometrically. The recoveries of neem oil from NOCU with oil load of 500 and 1000?ppm were 87.6?±?3.0% and 90.0?±?4.8% respectively with direct method; and improved to 92.6?±?4.0% and 96.7?±?3.8% after including the in situ purification. A simple method based on the Hantzsch reaction was developed for the determination of neem oil in NOCU. This method is superior to earlier methods in terms of sensitivity, simplicity, and time required. 相似文献
927.
Degradation of Acid Red I (ARI) dye by electrochemical treatment and UV light irradiation was studied in this work. The effect of the current density and the concentration of NaCl and dye on the decoloration and degradation efficiency were studied and optimized. The UV irradiation was monitored by UV-Vis spectrophotometry and chemical oxygen demand. The kinetic constants for decoloration and degradation were calculated. Degradation of 86% was achieved in 160?min and the first-order kinetic constant was 0.013?min?1. Degradation products were identified by gas chromatography/mass spectrometry. The mechanism for the degradation of ARI was proposed. 相似文献
928.
The frequent detection of antibiotics such as ciprofloxacin in surface and drinking waters around the world has attracted concern from various researchers. Such presence is an indication that the decontamination of water polluted by antibiotics is beyond the conventional treatment methods. However, among the different treatment methods that have been developed in the area of water purification, heterogeneous photocatalysis using semiconductor as a mediator has been rated as an efficient and a green wastewater treatment method. This is because, the process is effective in degrading and mineralizing organic pollutants, using UV or visible light. The present review paper covers a brief survey over a range of publications in the last decade, involving photocatalytic materials that have been employed in the purification of water contaminated by ciprofloxacin. 相似文献
929.
930.
在世界无车日期间对PM2.5化学组分、光学参数及气态污染物进行同步监测,评估机动车尾气排放对杭州市细颗粒物污染及能见度的影响.结果表明:管制期间NO2、NOx、CO和PM2.5浓度分别为45.0, 50.8, 1119, 85.8μg/m3,比平日分别下降了17.5%、23.3%、20.6%和32.6%.管制期间PM2.5中OC、EC和二次无机组分浓度为8.58, 4.29, 25.95μg/m3,比管制前下降了13.8%、12.6%和15.7%,管制后则达到20.24, 10.85, 27.39μg/m3,上升了136.0%、152.7%和5.5%.管制期间较高的NO3-/PM2.5和NOR(0.15)表明PM2.5的形成更多受二次无机转化影响,管制后PM2.5中上升的OC、EC比例和较低的NOR(0.07)则说明PM2.5主要来自机动车排放的碳质组分的贡献.硫酸盐、硝酸盐、有机气溶胶和EC是最主要的消光组分,共解释了总消光系数的74.0%~89.7%.管制后,机动车排放的有机物和EC消光比例达到26.6%和24.6%,大气消光系数则达到438.7Mm-1,比管制期间上升了60.5%,表明机动车污染排放已成为影响杭州大气细颗粒物污染和能见度下降的重要因素. 相似文献