全文获取类型
收费全文 | 8402篇 |
免费 | 666篇 |
国内免费 | 2791篇 |
专业分类
安全科学 | 669篇 |
废物处理 | 964篇 |
环保管理 | 1030篇 |
综合类 | 6250篇 |
基础理论 | 764篇 |
环境理论 | 2篇 |
污染及防治 | 1803篇 |
评价与监测 | 192篇 |
社会与环境 | 156篇 |
灾害及防治 | 29篇 |
出版年
2024年 | 9篇 |
2023年 | 46篇 |
2022年 | 107篇 |
2021年 | 148篇 |
2020年 | 157篇 |
2019年 | 155篇 |
2018年 | 179篇 |
2017年 | 234篇 |
2016年 | 269篇 |
2015年 | 353篇 |
2014年 | 513篇 |
2013年 | 593篇 |
2012年 | 735篇 |
2011年 | 775篇 |
2010年 | 612篇 |
2009年 | 673篇 |
2008年 | 462篇 |
2007年 | 815篇 |
2006年 | 890篇 |
2005年 | 645篇 |
2004年 | 528篇 |
2003年 | 544篇 |
2002年 | 472篇 |
2001年 | 383篇 |
2000年 | 327篇 |
1999年 | 268篇 |
1998年 | 207篇 |
1997年 | 160篇 |
1996年 | 139篇 |
1995年 | 136篇 |
1994年 | 90篇 |
1993年 | 80篇 |
1992年 | 40篇 |
1991年 | 30篇 |
1990年 | 21篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 8篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
A multi-year programme was performed to assess the effects of atmospheric ethylene on potato (Solanum tuberosum L.) in the vicinity of polyethylene manufacturing plants. There was a strong temporal variation of the hourly ethylene concentrations measured close to the sources from 1982 through 1991. Growing seasonal means exceeded 12 g m–3 ethylene, the threshold for phytotoxic effects under laboratory conditions. Young test plants of potato showed an epinastic response to enhanced levels of ethylene. This response was reversible and did not occur when atmospheric ethylene was not detected. Based on hourly observations for the growing seasons of 1984 through 1991, epinasty occurred on average during circa 5% of the growing season and varied from circa 1% in 1985 to circa 18% in 1991. At night, ethylene concentrations were higher and epinasty was more frequent than during daylight hours. The intermittent exposures to ethylene did not affect tuber yield for the growing seasons of 1982 through 1990. The occurrence of epinasty indicated that ethylene exposure levels in the vicinity of the industrial sources might be sufficiently high to affect sensitive plants. 相似文献
22.
23.
分光光度法测定染色废水的色度 总被引:3,自引:0,他引:3
为消除测定染色废水色度的主观误差,采用分光光度法测定染色废水的色度,与稀释倍数法相比,具有精确,重现性好,适用范围广等特点,PH值对色度的测定有明显影响,控制PH值为7.60,测定色度具有可比性。 相似文献
24.
25.
IntroductionTheo chlorophenolisaverytoxicandpoorlybiodegradablepollutant,whichisusedasanintermediateinthemanufactureofhigherchlorophenolandphenolresinsandforextractingsulphurandnitrogencompoundsfromcoals.Itisalsousedinorganicsynthesis(dyesandpesticide) .Oxidationofo chlorophenolwastewaterincatalyticwetairoxidationisofpracticalinterestsinceawastewatercontainingo chlorophenolover 2 0 0ppmmaynotbetreatedeffectivelybydirectbiologicalmethods.Advancedoxidationprocesses(AOPs)havebeensuccessfullyuse… 相似文献
26.
1IntroductionNovelbiologicalactivatedcarbonandactivatedsludgesystemhasshownitsefectiveabilitytoreduceCODintoxicorganicwastewa... 相似文献
27.
Based on wet air oxidation (WAO) and Fenton reagent, thispaper raises a new low pressure wet catalytic oxidation(LPWCO)which requires low pressure for the treatment of highlyconcentrated and refractory organic wastewater. Compared withgeneral wet air oxidation, the pressure of the treatment(0.1-0.6MPa) is only one of tens to percentage of latter(3.5-10MPa). Inaddition, its temperature is no more than 180℃.Compared withFenton reagent, while H2O2/COD(weight ratio) less than 1.2, theremoval of COD in the treatment is over twenty percents more thanFenton's even the value of COD is more than 14000mg/L. In thispaper, we study the effect factor of COD removal and the mechanismof this treatment. The existence of synergistic effect (catalytic oxidation and carbonization) for COD removal in H2SO4-Fenton reagent system under the condition of applied pressure and heating (0.1-0.6MPa, 104-165℃) was verified. The best condition of this disposal are as follows:H2O2/COD(weight ratio)=0.2-1.0, Fe2+ 0.6×10-3 mol, H2SO4 0.5mol, COD>1×104mg/L, the operating pressure is 0.1-0.6MPa and temperature is 104-165℃. This method suit to dispose the high-concentrated refractory wastewater, especially to the wastewater containing H2SO produced in the manufacture of pesticide, dyestuff and petrochemical works. 相似文献
28.
29.
通过对姑山矿生产现状的调查研究,确定审计重点为选矿车间,分析了选矿车间存在的问题,提出了清洁生产方案,对方案实施后的经济效益作了分析。 相似文献