全文获取类型
收费全文 | 1007篇 |
免费 | 193篇 |
国内免费 | 560篇 |
专业分类
安全科学 | 69篇 |
废物处理 | 58篇 |
环保管理 | 56篇 |
综合类 | 966篇 |
基础理论 | 329篇 |
污染及防治 | 211篇 |
评价与监测 | 55篇 |
社会与环境 | 12篇 |
灾害及防治 | 4篇 |
出版年
2023年 | 18篇 |
2022年 | 48篇 |
2021年 | 74篇 |
2020年 | 38篇 |
2019年 | 60篇 |
2018年 | 126篇 |
2017年 | 55篇 |
2016年 | 65篇 |
2015年 | 57篇 |
2014年 | 60篇 |
2013年 | 97篇 |
2012年 | 98篇 |
2011年 | 110篇 |
2010年 | 77篇 |
2009年 | 96篇 |
2008年 | 72篇 |
2007年 | 78篇 |
2006年 | 70篇 |
2005年 | 60篇 |
2004年 | 54篇 |
2003年 | 66篇 |
2002年 | 43篇 |
2001年 | 39篇 |
2000年 | 42篇 |
1999年 | 29篇 |
1998年 | 19篇 |
1997年 | 19篇 |
1996年 | 17篇 |
1995年 | 24篇 |
1994年 | 9篇 |
1993年 | 15篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有1760条查询结果,搜索用时 9 毫秒
691.
双道氢化物原子荧光法测定水和土壤中的砷 总被引:5,自引:0,他引:5
用AFS-2201双道氢化物发生原子荧光法测定水、土壤样品中的砷含量,方法简捷、快速、准确,二次污染物少.HNO3浓度大于5ppm时,对测量结果有影响.主机通过与微机相联可直接得出监测数据,大大减轻了监测人员的工作量,测定结果令人满意. 相似文献
692.
In this study, the authors have investigated the effects of various factors on both aerobic and anaerobic degradation of 4-t-octylphenol (4-t-OP) in granular sludge. In comparison, the aerobic degradation rate was much higher than that of anaerobic degradation. The optimal pH values for 4-t-OP degradation in granular sludge were 9 and 7 under aerobic and anaerobic conditions, respectively. And the degradation rate decreased with an increase in the initial 4-t-OP concentration. Addition of yeast extract or homologous compounds such as phenol also enhanced the 4-t-OP degradation, especially under the aerobic condition. To investigate the bacterial community in this study, the denaturing gradient gel electrophoresis (DGGE) method was applied, based on the primers, for the 16S rDNA V3 region of bacteria, γ-proteobacteria and bacillus were identified as the major species of sludge. 相似文献
693.
Urea hydrolysis and recovery of nitrogen and phosphorous as MAP
from stale human urine 总被引:1,自引:0,他引:1
LIU Zhigang ZHAO Qingliang WANG Kun LEE Duujong QIU Wei WANG Jianfang 《环境科学学报(英文版)》2008,20(8):1018-1024
Laboratory-scale tests for magnesium ammonium phosphate(MAP)precipitation following urea hydrolysis of human urine were conducted using orthogonal experiment design.The effects of initial pH,temperature and the volumetric ratios of stale urine to fresh urine,on urea hydrolysis in urine were studied to determine the final hydrolysis time to recover most nitrogen from separated human urine by MAP.With a volumetric ratio of stale to fresh urine>10% and at temperature≥20℃,urea hydrolysis could be completed i... 相似文献
694.
Adsorption behavior of Azo Dye C. I. Acid Red 14 in aqueous solution
on surface soils 总被引:2,自引:1,他引:1
QU Baocheng ZHOU Jiti XIANG Xuemin ZHENG Chunli ZHAO Hongxi ZHOU Xiaobai 《环境科学学报(英文版)》2008,20(6):704-709
Azo dyes have received considerable attention because of their association with various human health problems. The aim of the investigation is to determine the adsorption behavior ofazo dyes in aqueous solution on DG06, GSE17200, and GSE17201 soils using C. I. Acid Red 14 (AR14) as example. The experimental results indicate that the Freundlich model expresses the adsorption isotherm better than the Langmuir model and the pseudo-second-order model achieves adsorption of AR14 on the three soils well. Based on the pseudo-second-order model, the adsorption thermodynamic of AR14 on DG06 soil have been studied and the thermodynamics parameter of AGO is determined and AGO value shows the adsorption process of AR14 on DG06 is mainly physical in nature. Furthermore, the effects of temperature, pH and salinity (NaC1) on adsorption have been investigated. The decrease in pH or the increase in salinity enhances the adsorption of AR14 by DG06, GSE17200, and GSE17201. 相似文献
695.
一种新技术的问世,驱动着经济社会的大发展、大变革,4G时代的到来再一次把移动通信技术推向另一个高端平台,其推广应用也成为了各企业在行业中崭露头角的关键法宝.智慧旅游是一种需要移动通信技术作为核心支撑而发展的新型旅游,必将在未来旅游业中迅速崛起.着眼4G于实际,放眼智慧旅游于未来,从智慧旅游和4G技术的概念以及发展历程着手,挖掘了4G与智慧旅游发展的内在关系.以武夷山风景区作为实例,分析了当地资源状况和智慧旅游发展现状,并从以政府为代表的管理机构、旅游企业、旅游者、目的地居民角度出发,提出武夷山风景区智慧旅游开发的对策. 相似文献
696.
C.R.M. Attard L.M. Möller M. Sasaki M.P. Hammer C.M. Bice C.J. Brauer D.C. Carvalho J.O. Harris L.B. Beheregaray 《Conservation biology》2016,30(5):1060-1069
Research in reintroduction biology has provided a greater understanding of the often limited success of species reintroductions and highlighted the need for scientifically rigorous approaches in reintroduction programs. We examined the recent genetic‐based captive‐breeding and reintroduction literature to showcase the underuse of the genetic data gathered. We devised a framework that takes full advantage of the genetic data through assessment of the genetic makeup of populations before (past component of the framework), during (present component), and after (future component) captive‐breeding and reintroduction events to understand their conservation potential and maximize their success. We empirically applied our framework to two small fishes: Yarra pygmy perch (Nannoperca obscura) and southern pygmy perch (Nannoperca australis). Each of these species has a locally adapted and geographically isolated lineage that is endemic to the highly threatened lower Murray–Darling Basin in Australia. These two populations were rescued during Australia's recent decade‐long Millennium Drought, when their persistence became entirely dependent on captive‐breeding and subsequent reintroduction efforts. Using historical demographic analyses, we found differences and similarities between the species in the genetic impacts of past natural and anthropogenic events that occurred in situ, such as European settlement (past component). Subsequently, successful maintenance of genetic diversity in captivity—despite skewed brooder contribution to offspring—was achieved through carefully managed genetic‐based breeding (present component). Finally, genetic monitoring revealed the survival and recruitment of released captive‐bred offspring in the wild (future component). Our holistic framework often requires no additional data collection to that typically gathered in genetic‐based breeding programs, is applicable to a wide range of species, advances the genetic considerations of reintroduction programs, and is expected to improve with the use of next‐generation sequencing technology. 相似文献
697.
采用HPLC—UV及GC—MS技术鉴定了灭幼脲(Ⅲ)在水相中的表观光解产物,通过分析表观光解反应与暗反应产物的相对含量,确认对氯苯基异氰酸酯和邻氯苯甲酰胺是灭幼脲(Ⅲ)在永相中光解的主要产物。另外,依据反应产物的组成和相对含量,对灭幼脲(Ⅲ)在水相中的光解反应速率常数作了估算。 相似文献
698.
This paper describes a case of pseudomosaic centric fission of chromosome 4 detected in amniotic fluid cell culture. The pregnancy went to term and the newborn had a normal chromosomal constitution. 相似文献
699.
1997年5月中美联合珠峰地区绒布冰川考察期间,在远东绒布冰川海拔6500m北支冰流粒雪盆内钻取到一支41m长冰芯.该冰芯定年至1814年.远东绒布冰芯中近200年来草酸根浓度变化与Ca2+和NH4浓度变化一致性较差,表明草酸根的来源有别于大气尘埃和生物来源.草酸根浓度与冰芯中气温指标δ18O的变化具有一致性,说明气温是影响大气中草酸根浓度变化的因素之一,但非主导因素.远东绒布冰芯记录的20世纪以来草酸根浓度的迅速升高反映了人类工业活动对大气环境的污染.20世纪50~80年代,大气中受人类工业活动污染的草酸根浓度约为19世纪自然本底值的3倍,其中60年代人类活动排放的草酸盐类对大气的污染最为严重. 相似文献
700.
硫酸铜对亚硫酸钠除氧性能的影响 总被引:1,自引:0,他引:1
研究了Na2 SO3的除氧性能与特点 ,讨论了 pH值、水的温度、Na2 SO3的过剩以及添加剂CuSO4 对Na2 SO3除氧性能的影响。实验结果表明 :单独使用Na2 SO3除氧 ,除氧率最高 ,仅能达到 90 % ,而且Na2 SO3的用量过大 ,对水泵有负面的影响。pH值约在 5到 9之间除氧效果较好 ,水温越高 ,除氧效果越好。CuSO4 的添加能够明显提高Na2 SO3的除氧性能 ,且降低Na2 SO3的使用量。当Na2 SO3的加入量是理论加入量约为 6.0mg/L ,CuSO4 的加入量为 2 .0mg/L时 ,除氧率大于99 .5 % ,且pH值在 7~ 11之间 ,除氧率变化很小 相似文献