全文获取类型
收费全文 | 8193篇 |
免费 | 960篇 |
国内免费 | 1753篇 |
专业分类
安全科学 | 2117篇 |
废物处理 | 684篇 |
环保管理 | 995篇 |
综合类 | 4733篇 |
基础理论 | 618篇 |
环境理论 | 5篇 |
污染及防治 | 930篇 |
评价与监测 | 539篇 |
社会与环境 | 179篇 |
灾害及防治 | 106篇 |
出版年
2024年 | 16篇 |
2023年 | 107篇 |
2022年 | 196篇 |
2021年 | 300篇 |
2020年 | 295篇 |
2019年 | 283篇 |
2018年 | 234篇 |
2017年 | 323篇 |
2016年 | 371篇 |
2015年 | 449篇 |
2014年 | 496篇 |
2013年 | 649篇 |
2012年 | 747篇 |
2011年 | 731篇 |
2010年 | 548篇 |
2009年 | 540篇 |
2008年 | 367篇 |
2007年 | 635篇 |
2006年 | 623篇 |
2005年 | 435篇 |
2004年 | 354篇 |
2003年 | 358篇 |
2002年 | 304篇 |
2001年 | 271篇 |
2000年 | 256篇 |
1999年 | 210篇 |
1998年 | 173篇 |
1997年 | 145篇 |
1996年 | 128篇 |
1995年 | 92篇 |
1994年 | 68篇 |
1993年 | 51篇 |
1992年 | 55篇 |
1991年 | 28篇 |
1990年 | 23篇 |
1989年 | 11篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1982年 | 2篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 5篇 |
1971年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
41.
湿法吸收测定大气中的五氧化二磷 总被引:1,自引:0,他引:1
用2%NaOH溶液吸收大气中的P2O5,用钼锑抗试剂显色定量。对样品的稳定性、方法的显色条件、精密度、准确度以及检出限进行反复试验,结果令人满意。 相似文献
42.
尝试了使用5%钼酸铵-5%磷酸二氢铵溶液组成石墨管连续涂覆结合基体改进剂的方法,应用于地表水Pb的测量中。实验表明,本法具有提高石墨管在使用过程中的稳定性,消除基体效应的作用。 相似文献
43.
对螯合树脂在线富集,火焰原子吸收光度法进行了条件试验。试验证实方法对Cu、Pb、Zn、Cd4个元素检出浓度可达μg/L级,校准曲线性、样品重现性及准确度可满足测定要求。 相似文献
44.
45.
采用火焰原子吸收分光光度法测定鱼内脏及河流底泥中的铜。鱼内脏经组织捣碎机捣成匀浆后,加硝酸消解;底泥则经氢氟酸和高氯酸消化。该方法具有灵敏度高,精密度和回收率较好等特点。 相似文献
46.
A membrane extraction-gas chromatography method was developed fordetermination of organophosphorus pesticides and related compounds including methamidophos, DDVP, dimethoate, methyl parathion, parathion, thiophosphoric acid trimethyl ester, and thiophosphoramidic acid dimethyl ester in water samples. In thismethod, surface-modified acetic cellulose membranes were used to extract the target analytes in water samples, the extracted analytes were back-extracted into a small amount of methanol, andgas chromatography with pulsed flame photometric detector (GC-PFPD) was used to determine the concentrations of targetanalytes in the extracts. The recoveries obtained for thetarget analytes spiked into the water samples ranged from 66to 94%. The method detection limit for each target analyte was 0.05 g L-1. The method developed in this study had shown the advantages of being cheap, simple, fast, and reliable. It had been used successfully to determine the concentrations of target analytes in river water samples. 相似文献
47.
Goyal SK 《Environmental monitoring and assessment》2003,89(3):305-314
Sodium arsenite (modified Jacobs and Hochheiser method; hereafter referred as SA), the most widely used manual monitoring method for determination of nitrogen dioxide (NO2) in ambient air, particularly in developing countries has been evaluated and compared with US EPA recommended equivalent method of TGS-ANSA (hereafter referred as ANSA). NO2 concentrations generated from laboratory test atmosphere were analyzed by these two methods and were compared statistically. Laboratory evaluations showed that SA method has high sensitivity to different sampling conditions, which normally vary during actual field monitoring. Hence, correction factors for absorption efficiency were estimated for SA and ANSA methods. Absorption efficiency of NO2 in SA method was found to be much lower (64%) as against the reported value of 82% at the method recommended sampling conditions, whereas for ANSA method, it was found 1.0 as against the reported value of 0.93. After applying derived correction factors, both the methods produced almost similar concentration values of NO2. 相似文献
48.
Butter (45) and ghee (55) samples were collected from rural and urban areas of cotton growing belt of Haryana and analysed for detecting the residues of organochlorine, synthetic pyrethroid and organophosphate insecticides. The estimation was carried out by using multi residue analytical technique employing GC-ECD and GC-NPD systems equipped with capillary columns. Butter samples were comparatively more contaminated (97%) than ghee (94%), showing more contamination with organochlorine insecticides from urban samples. About 11% samples of butter showed endosulfan residues above MRL value and 2% samples had residues of synthetic pyrethroids and organophosphates each above their respective MRL values. In ghee, residues of HCH & DDT both and of endosulfan exceeded the MRL values in 5 and 20% samples, respectively. Among organophosphates, only chlorpyriphos was detected with 9% samples showing its residue above MRL value. Irrespective of contamination levels, residues above the MRL values were more in ghee. More extensive study covering other agricultural regions/zones of Haryana has been suggested to know the overall scenario of contamination of milk products. 相似文献
49.
乌鲁木齐市汽车尾气排污现状及防治对策探讨 总被引:1,自引:0,他引:1
对乌鲁木齐市在用车辆进行了路抽检调查,通过大量数据分析,得出乌鲁木齐市目前汽车尾气排放情况仍令人担忧,治理工作不容忽视。 相似文献
50.