全文获取类型
收费全文 | 18219篇 |
免费 | 2052篇 |
国内免费 | 8489篇 |
专业分类
安全科学 | 2408篇 |
废物处理 | 1147篇 |
环保管理 | 2129篇 |
综合类 | 15389篇 |
基础理论 | 3118篇 |
环境理论 | 5篇 |
污染及防治 | 2914篇 |
评价与监测 | 879篇 |
社会与环境 | 517篇 |
灾害及防治 | 254篇 |
出版年
2024年 | 59篇 |
2023年 | 520篇 |
2022年 | 783篇 |
2021年 | 935篇 |
2020年 | 906篇 |
2019年 | 937篇 |
2018年 | 869篇 |
2017年 | 795篇 |
2016年 | 983篇 |
2015年 | 1072篇 |
2014年 | 1287篇 |
2013年 | 1784篇 |
2012年 | 1873篇 |
2011年 | 1889篇 |
2010年 | 1354篇 |
2009年 | 1579篇 |
2008年 | 1270篇 |
2007年 | 1542篇 |
2006年 | 1570篇 |
2005年 | 1107篇 |
2004年 | 879篇 |
2003年 | 828篇 |
2002年 | 648篇 |
2001年 | 574篇 |
2000年 | 524篇 |
1999年 | 442篇 |
1998年 | 317篇 |
1997年 | 257篇 |
1996年 | 228篇 |
1995年 | 217篇 |
1994年 | 154篇 |
1993年 | 140篇 |
1992年 | 99篇 |
1991年 | 52篇 |
1990年 | 45篇 |
1989年 | 27篇 |
1988年 | 21篇 |
1987年 | 17篇 |
1986年 | 16篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1983年 | 16篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 14篇 |
1979年 | 9篇 |
1977年 | 5篇 |
1973年 | 8篇 |
1972年 | 5篇 |
1971年 | 36篇 |
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
111.
Fractionation of Cu, Pb and Zn in certified reference soils SRM 2710 and SRM 2711 using the optimized BCR sequential extraction procedure 总被引:4,自引:0,他引:4
Sequential extraction of metals from solid media is a common analytical tool used in environmental and exploration geochemistry. A number of procedures exist, but without harmonization and standardization, meaningful comparisons are tenuous without baseline data. A newly developed, standardized sequential extraction procedure (optimized BCR) was applied to two contaminated certified reference soils from Montana, US (SRM 2710 and SRM 2711) for Cu, Pb and Zn. Four operationally defined fractions were isolated, acid extractable, reducible, oxidizable, and residual (by aqua regia). Fraction-specific concentrations, percentages and recoveries for Cu, Pb and Zn were used to explore differences between the optimized BCR procedure and three other sequential extraction schemes with published data for SRM 2710 and 2711 (i.e. Tessier scheme, Geological Survey of Canada scheme and the original BCR scheme). Results indicate significant differences between the four schemes, even for schemes that are closely associated (i.e. the original and optimized BCR schemes). Order-of-magnitude fraction-specific concentration differences were observed, especially for Pb in the reducible fraction. Differences between schemes are worrisome because trends varied between metals, between fractions and between reference soils. These data reinforce the need for increased adoption of standardized sequential extraction procedures and further examination of different solid media. 相似文献
112.
硝化反应及其控制因素 总被引:7,自引:0,他引:7
对硝化菌和亚硝化菌的特性进行了分析,并就碳源不足的废水实行短程硝化—反硝化脱氮的途径进行探讨。 相似文献
113.
114.
三维虚拟地理环境构建与应用 总被引:2,自引:0,他引:2
可量测三维虚拟地理环境是数字地球应用的基础平台。本文研究了三维虚拟地理环境构建空间几何建模与纹理建模关键技术。提出了一种适用于大规模生产建库的可量测三维虚拟地理环境构建的生产工艺模型和三维虚拟模型数据获取的方法。介绍了三维虚拟地理环境在城市规划、房产经营管理等方面的应用。 相似文献
115.
IntroductionEightypercentoforganicsubstancesinthesourcewaterisfromcrudehumicacidthatisacrudeorganiccompoundcreatedbyrottinganddecomposinginnaturalcycle ,thehighercontentofhumicacidis ,theworsequalityofthewateris,notonlycanitcausechrominance,offensiveodor,… 相似文献
116.
分光光度法测定雨水中微量过氧化氢的研究 总被引:1,自引:0,他引:1
本文提出了以钛(IV) 过氧化氢 2 (3,5 二溴 2 吡啶偶氮) 5 二乙氨基苯酚(3,5 diBr PADAP)三元配合物体系光度测定雨水中微量过氧化氢的方法,该方法简便,灵敏度和选择性较高,所得结果令人满意 相似文献
117.
Li Ning Li Guangming Yao Zhenya Zhao Jianfu 《Frontiers of Environmental Science & Engineering in China》2007,1(2):190-195
Catalytic wet air oxidation (CWAO) is one of the most promising technologies for pollution abatement. Developing catalysts
with high activity and stability is crucial for the application of the CWAO process. The Mn/Ce complex oxide catalysts for
CWAO of high concentration phenol-containing wastewater were prepared by coprecipitation. The catalyst preparation conditions
were optimized by using an orthogonal layout method and single-factor experimental analysis. The Mn/Ce serial catalysts were
characterized by Brunauer-Emmett-Teller (BET) analysis and the metal cation leaching was measured by inductively coupled plasma
torch-atomic emission spectrometry (ICP-AES). The results show that the catalysts have high catalytic activities even at a
low temperature (80°C) and low oxygen partial pressure (0.5 MPa) in a batch reactor. The metallic ion leaching is comparatively
low (Mn<6.577 mg/L and Ce<0.6910 mg/L, respectively) in the CWAO process. The phenol, CODCr, and TOC removal efficiencies in the solution exceed 98.5% using the optimal catalyst (named CSP). The new catalyst would
have a promising application in CWAO treatment of high concentration organic wastewater.
Translated from Techniques and Equipment for Environmental Pollution Control, 2005, 6(2): 40–44 [译自: 环境污染治理技术与设备] 相似文献
118.
对多环芳烃(PAHS)4种理化参数(K;W、Sw。X Vv。)与 LCO的相关关系进行了研究,建立了 4种一元线性回归方程。结果表明,4种参数的相关系数分别为:0.刀66、08083、09488、0.9570,经r检验,后两种属高度显著相关.用所建立的一元线性回归方程对7种PAHS的LC。进行估算,估算值与实测值相比,平均相对误差分别为58.84%、32.23%、1761%、198%,用l和V*.H对LClj进行估算的估算精度也较高。经比较,提出用(。估算P*比对麦穗鱼*CO的新方法。 相似文献
119.
IntroductionTheo chlorophenolisaverytoxicandpoorlybiodegradablepollutant,whichisusedasanintermediateinthemanufactureofhigherchlorophenolandphenolresinsandforextractingsulphurandnitrogencompoundsfromcoals.Itisalsousedinorganicsynthesis(dyesandpesticide) .Oxidationofo chlorophenolwastewaterincatalyticwetairoxidationisofpracticalinterestsinceawastewatercontainingo chlorophenolover 2 0 0ppmmaynotbetreatedeffectivelybydirectbiologicalmethods.Advancedoxidationprocesses(AOPs)havebeensuccessfullyuse… 相似文献
120.
The landfill of municipal solid waste(MSW) could be regarded as denitrification reactor and involved in ammonia nitrogen biological removal process. In this research, the process was applied to municipal solid waste collected in Shanghai, China, which was characterized by high food waste content. The NH4^ removal efficiency in the system of SBR nitrifying reactor followed by fresh and matured landfilled waste layer in series was studied. In the nitrifying reactor, above 90% of NH4^ in leachate was oxidized to NO2^- and NO3^- . Then high concentrated NO2^- and NO3^- were removed in the way of denitrification process in fresh landfilled waste layer. At the same time, degradation of fresh landfilled waste was accelerated. Up to the day 120, 136.5 gC/(kg dry waste) and 17.9 gN/(kg dry waste) were converted from waste layer. It accounted for 50.15 % and 86.89 % of the total carbon and nitrogen content of preliminary fresh waste, which was 4.42 times and 5.17 times higher than that of reference column respectively. After filtering through matured landfilled waste, BOD5 concentration in leachate dropped to below 100 mg/L, which would not affect following nitrification adversely. Because the matured landfilled waste acted as a well methanogenic reactor, 23% of carbon produced accumulatively from fresh landfilled waste degradation was converted into CH4. 相似文献