全文获取类型
收费全文 | 132篇 |
免费 | 1篇 |
国内免费 | 17篇 |
专业分类
安全科学 | 29篇 |
废物处理 | 6篇 |
环保管理 | 13篇 |
综合类 | 53篇 |
基础理论 | 14篇 |
污染及防治 | 27篇 |
评价与监测 | 3篇 |
社会与环境 | 3篇 |
灾害及防治 | 2篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 6篇 |
2020年 | 6篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 10篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 17篇 |
2012年 | 6篇 |
2011年 | 10篇 |
2010年 | 3篇 |
2009年 | 9篇 |
2008年 | 6篇 |
2007年 | 13篇 |
2006年 | 8篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 2篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有150条查询结果,搜索用时 15 毫秒
71.
Shinso Yokota Kazuya Iizuka Futoshi Ishiguri Zensaku Abe Nobuo Yoshizawa 《Journal of Material Cycles and Waste Management》2006,8(2):140-144
Delignification from the cell walls with a combination of ozone oxidation and dioxane–water extraction using thin sections
of a softwood, Japanese cypress (Chamaecyparis obtusa Endl.), was studied to determine its suitability for the production of recyclable cellulose-based materials from wood waste.
The visible-light absorption spectra of treated wood sections revealed that delignification from the cell walls with ozone
increased with increasing ozonization time. Ozone delignification proceeded from the lumen side toward the middle lamella
within the secondary wall of a cell, and it proceeded faster in early wood than in late wood within an annual ring. Mild ozonization
for 10–30 min was sufficient for the removal of lignin from the cell walls when sections were extracted with dioxane after
ozonization. The results obtained here demonstrate that microspectrometry coupled with the Wiesner reaction is useful for
the quantitative analysis of lignin in cell walls. 相似文献
72.
稀土金属离子对梨形四膜虫的24小时生长影响 总被引:1,自引:0,他引:1
应用4种方法(细胞直计计数法、中性红试验、重蛋白及核酸含量测定)研究不同浓度稀土金属离子La^2+、Sm^3+、Y^3+、Gd^3+处理24h后,对梨形四膜虫的生长影响,结果表明,在低浓度时La^3+、Sm^3+、Y^3+,对四膜虫具有刺激生长的作用。随着浓度的升高,4种稀土金属离子均表现出毒性效应;高浓度时,抑制生长艇特别明显。计算La^3+、Sm^3+、Y^3+、Gd^3+的半数抑制浓度(IC 相似文献
73.
Bing Feng Chunbo Wang Xingqiang Wu Cuicui Tian Meng Zhang Yingying Tian Bangding Xiao 《环境科学学报(英文版)》2019,31(10):184-196
Lake Caohai has experienced extensive Microcystis blooms in recent years,and to improve its water quality,the local government carried out a series of water control measures.To better understand the dynamics of both pelagic and benthic Microcystis and their characteristics in Lake Caohai,we conducted a 1-year investigation from December 2015to December 2016 to gain a seasonal outlook on the distribution and dynamics of cell abundance,colony size and intracellular microcystins(MCs)of Microcystis.The results indicated that the Microcystis bloom occupied primarily the northeastern region and then moved gradually from lakeshore to lake center.The perennial southwesterly winds and the water inflow from northeast to southwest in Lake Caohai determined the spatiotemporal distribution of pelagic Microcystis.Benthic Microcystis was mainly distributed in the northeastern region in summer,occupied the lake center in autumn and then occupied the southeastern region in winter,determined by the sedimentation of pelagic Microcystis and the death of benthic Microcystis.Small colonies(20-60μm)overwintered more easily in both water column and sediment.The concentrations of intracellular toxin of benthic Microcystis were observed to be significantly higher than those of pelagic Microcystis.This might be because Microcystis synthesized large amount of MCs to acclimate to an unfavorable benthic environment.This knowledge on the dynamics of Microcystis expands our understanding of mechanisms underpinning the formation of Microcystis blooms. 相似文献
74.
The current study considered, for the first time, compensatory decisions within the theory of planned behaviour (TPB) to explain why people use mobile phones while driving. The effects of age, gender, and mobile phone mode on respondents’ answering intentions and compensatory decisions were mainly examined. A series of questions were administered to 333 drivers (ages 25-59), which included (1) demographic measures, (2) scales that measured prior mobile use activities in both driving and ordinary contexts, (3) a question to measure drivers’ perceptions of the safety of hands-free phones, and (4) TPB measures, which measured answer intention and two compensatory behavioural decisions (i.e., reminding the caller that he/she is driving, limiting the length of a conversations (including perceived its limits)), along with predictive variables. Drivers reported a moderate likelihood of answering intention and a strong tendency to engage in the two compensatory behaviours. Answering intention and compensatory decisions, perceived behavioural control, perceived risk, and usage frequency were more dependent on mobile phone mode and age group than gender. The regression models explained 64% and 67% of the variance in answering intention in the handheld and hands-free scenario separately. Attitudes, subjective norms, perceived behavioural risk and control (PBRC), and prior answering behaviour emerged as common predictors. The predictive models explained 31% and 37% of the variance for perceived limits of a conversation length in handheld and hands-free scenarios, respectively. Answering intention and PBRC consistently predicted most of the variance (handheld: 28%; hands-free: 32%) for this compensatory perception limits. The theoretical and practical implications of these results are discussed. 相似文献
75.
76.
77.
污水生物处理系统中内源过程的研究进展 总被引:4,自引:0,他引:4
污水生物处理系统的内源过程涉及到一系列微生物学、生态学机制和过程,因而对处理系统的各个方面都有重要影响.然而-目前对内源过程的认识还相当有限.本文首先在总结现有知识的基础上对污水生物处理系统中的内源过程作了定义,并对其区分为细胞和群落两个水平-随后,分别对内源过程中的细胞维持、解偶联、程序化细胞死亡、饥饿状态、高等微生物捕食等过程作了综述,总结了其在污水生物处理领域的研究进展.此外.文章还概述了细胞维持能量和细胞衰减速率的测定方法及其研究进展和存在的问题.本文的目的是通过综述现有的知识,推动对污水生物处理系统中内源过程研究的进一步发展. 相似文献
78.
Introduction: The use of mobile phones while driving is known to be a distraction factor and a cause of accidents. The way in which different kinds of conversations affect the behavioral performance of the driver as well as the persistence of the effects are not yet fully understood. Method: In this study, in addition to comparing brain function and behavioral function in dual task conditions in three conversations types, the persistent effects of these types of conversations have also been traced. Results: The results show that the content of the mobile phone conversation while driving is the cause of the persistent changes in behavioral and brain functions. Increased time headway and lane departure was observed during and up to 5 min after the emotional conversation was finished. EEG bands also varied in different types of conversations. Cognitive conversations caused an increase in the activity of the alpha and beta bands while emotional conversations enhanced the rate of gamma and beta bands. A meaningful correlation was found between changes in the theta and alpha bands and changes in behavioral performance both during the dual task condition and after the conversation was finished, was also observed. Conclusions: The content of the conversation is one of the most important factors that increase the risk of road accidents. This can also deteriorate the behavioral performance of the driver and can have persistent effects on behavioral performance and the brain. Practical applications: The findings of this study provide a basis to measure and tracing drivers’ cognitive distractions induced by different levels of mental workload through physiological and behavioral performances. 相似文献
79.
人工神经网络法在大气污染预报中的应用 总被引:3,自引:0,他引:3
以鞍山市为例,应用人工神经网络方法,模拟人脑的思维方式,建立了大气污染物浓度的神经网络预报模型,并将计算结果与监测值进行了对比验证,计算结果表明,BP模型应用于大气污染物浓度预报具有较高的预报精度。 相似文献
80.
Copper availability and bioavailability are controlled by rhizosphere pH in rape grown in an acidic Cu-contaminated soil 总被引:1,自引:0,他引:1
Valérie Chaignon 《Environmental pollution (Barking, Essex : 1987)》2009,157(12):3363-3369
We evaluated how root-induced changes in rhizosphere pH varied and interacted with Cu availability and bioavailability in an acidic soil. Rape was grown on a Cu-contaminated acidic soil, which had been limed at 10 rates. Soil Cu bioavailability was not influenced by liming. However, liming significantly decreased CaCl2-extracted Cu for pH between 3.7 and 5.1. Little effect was found for pH above 5.1. For soil pH < 4.4, CaCl2-Cu contents were smaller in rhizosphere than uncropped soil. Rhizosphere alkalisation occurred at pH < 4.8, while acidification occurred at greater pH. This explained the changes of CaCl2-Cu in the rhizosphere at low pH and the absence of pH dependency of Cu bioavailability to rape. In addition, apoplastic Cu in roots increased with increasing soil pH, most probably as a result of increased dissociation and affinity of cell wall compounds for Cu. 相似文献