全文获取类型
收费全文 | 263篇 |
免费 | 29篇 |
国内免费 | 15篇 |
专业分类
安全科学 | 97篇 |
废物处理 | 1篇 |
环保管理 | 13篇 |
综合类 | 82篇 |
基础理论 | 81篇 |
环境理论 | 1篇 |
污染及防治 | 7篇 |
评价与监测 | 8篇 |
社会与环境 | 4篇 |
灾害及防治 | 13篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 12篇 |
2020年 | 12篇 |
2019年 | 9篇 |
2018年 | 3篇 |
2017年 | 12篇 |
2016年 | 8篇 |
2015年 | 12篇 |
2014年 | 6篇 |
2013年 | 7篇 |
2012年 | 15篇 |
2011年 | 20篇 |
2010年 | 11篇 |
2009年 | 25篇 |
2008年 | 20篇 |
2007年 | 18篇 |
2006年 | 18篇 |
2005年 | 14篇 |
2004年 | 19篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有307条查询结果,搜索用时 296 毫秒
81.
82.
重大工业事故隐患辨识与评价方法研究 总被引:2,自引:2,他引:2
从导致事故发生的两类危险源理论出发,结合重大危险源和重大工业事故隐患之间的相互关系,揭示进行重大工业事故隐患辨识和评价的本质就是对危险控制措施和控制能力的评价,即对重大危险源采取的控制措施是否到位,能否有效控制事故的发生。该方法通过对工业单元固有的事故易发性和所采取措施的控制能力二者之间是否满足必要的受控关系,作为重大危险源是否构成重大工业事故隐患的判断依据。在工业生产中的应用该法,可以客观反映危险源的危险控制情况,便于危险源所在单位及时加强技术干预,减少事故发生。 相似文献
83.
Antoine?O.H.C.?Leduc Maud?C.O.?Ferrari Jocelyn?M.?Kelly Grant?E.?BrownEmail author 《Chemoecology》2004,14(2):107-112
Summary. Recent studies have demonstrated that under
weakly acidic conditions (pH 6.0), many prey fishes, including
juvenile rainbow trout (Onchorhynchus mykiss), do not
exhibit overt antipredator responses to conspecific chemical
alarm cues. In laboratory trials, we investigated the potential
effects of reduced pH on the ability of hatchery reared, predator
naïve juvenile rainbow trout to acquire the recognition of
a novel predator (yellow perch, Perca flavenscens). Initially,
we exposed trout to the odour of a predatory yellow perch,
buffered to pH 6.0 (weakly acidic) or pH 7.0 (neutral) paired
with conspecific skin extracts (also buffered to pH 6.0 or 7.0)
or a distilled water control. Juvenile trout exhibited significant
increase in antipredator behaviour when exposed to neutral
skin extract (pH 7.0). When retested 48 hours later to perch
odour alone (pH 7.0), only trout initially conditioned with
neutral skin extracts (pairs with either neutral or acidic perch
odour) exhibited a learned recognition of perch odour as a
predator risk. Those initially exposed to weakly acidic skin
extract or the distilled water control did not show a learned
response to predator odour. These results demonstrate that the
ability to acquire the recognition of novel predators is
impaired under weakly acidic conditions, as would occur in
natural waterways affected by acidic precipitation. 相似文献
84.
We studied the factors that enhance food recognition and consumption in young canaries when confronted with adults. In contrast
to previous studies on canaries, in which social transmission of food habits was studied in the context of dyadic interactions
(one juvenile–one adult), we proposed a more realistic framework in which young canaries were studied in the context of triadic
interactions, free or not, with adults of both sexes. We found that during free interactions, the young bird only eats with
a familiar male and that this association enhances the social transmission of seed handling. When the juvenile was separated
from the adults by a transparent partition, it only learned to husk seed if it was present at the feeder at the same time
as a familiar adult acting as a demonstrator. The presence of adults that are familiar but do not act as demonstrators does
not facilitate social transmission of handling. However, the presence of a familiar, demonstrating female had also no effect
on this transmission. Coordination of the actions of the experienced bird and of the naive subject is required for social
transmission to occur. Action coordination does not depend solely on the level of familiarity between partners but also on
the role played by the demonstrator (here, the adult male) that looks after the juvenile during its transition towards independence. 相似文献
85.
Sandra Steiger Klaus Peschke Josef K. Müller 《Behavioral ecology and sociobiology》2008,62(7):1053-1060
Nestmate recognition in eusocial insects has received a lot of attention in the last decades. Recognition in subsocial species,
in contrast, has been ignored almost completely and consequently, and little is known about proximate mechanisms of recognition
in subsocial systems. We studied one subsocial species, the biparental brood caring burying beetle Nicrophorus vespilloides, an interesting model organism for studies of recognition because of its ability to discriminate between breeding partners
and conspecific competitors. Recognition appears to be based on a chemical cue closely linked to the breeding status of individuals.
Breeding and non-breeding beetles consistently differ in their relative proportions of polyunsaturated cuticular hydrocarbons.
To investigate the function of these polyenes in the burying beetles’ recognition system, we quantified their concentration
on the cuticle during the early state of a breeding attempt and tested the response of breeding beetles in corresponding behavioural
experiments. We observed a rapid increase in the proportion of polyunsaturated hydrocarbons of both males and females after
they were provided with a carcass suitable for reproduction. Furthermore, we found that the relative amount of polyenes on
an individual’s surface was closely correlated with its chance of being accepted as breeding partner. Our results support
the idea that polyunsaturated hydrocarbons are involved in breeding partner recognition in N. vespilloides, functioning as a signal that conveys information about the individual’s breeding status. Breeding females have greater amount
of polyenes than breeding males, and females ingest more carrion during the first days on the carcass, which supports our
hypothesis that precursors for the respective polyenes are derived from ingested carrion. 相似文献
86.
87.
Does the potential safety risk affect whether particular construction hazards are recognized or not?
Introduction: Evidence from the global construction industry suggests that an unacceptable number of safety hazards remain unrecognized in construction workplaces. Unfortunately, there isn’t a sufficient understanding of why particular safety hazards remain unrecognized. Such an understanding is important to address the issue of poor hazard recognition and develop remedial interventions. A recent exploratory effort provided anecdotal evidence that workers often fail to recognize safety hazards that are expected to impose relatively lower levels of safety risk. In other words, the research demonstrated that the underlying risk imposed by a safety hazard can affect whether a hazard will be recognized or not. Method: The presented research focused on empirically testing this preliminary finding. More specifically, the study tested the proposition that Construction workers are more likely to recognize safety hazards that impose higher levels of safety risk than those that impose relatively lower levels of safety risk. The research goals were accomplished through a number of steps. First, a set of 16 construction case images depicting a variety of construction operations that included a number of known safety hazards was presented to a panel of four construction safety experts. The experts were tasked with examining each of the known safety hazards and providing a rating of the relative safety risk that the individual hazards impose. Having obtained an estimate of the underlying safety risk, a hazard recognition activity was administered to 287 workers recruited from 57 construction workplaces in the United States. The hazard recognition activity involved the examination of a random sample of two construction case images that were previously examined by the expert panel and reporting relevant safety hazards. Results: The results of the study provided support for the proposition that workers are more likely to recognize hazards that impose relatively higher levels of safety risk. Practical Applications: The findings of the study can be leveraged to improve existing hazard recognition methods and develop more robust interventions to address the issue of poor hazard recognition levels. 相似文献
88.
本文利用模糊模式识别交叉迭代模型对分布于乌梁素海各水功能区的21个水质监测点,2009年5月~10月的富营养化等级进行了模糊模式识别研究;并利用Arcview的空间分析功能,绘制富营养化等级识别结果的空间分布月变化Grid图。将富营养化状态识别结果及其分布区域与乌梁素海同期水质监测指标浓度变化及其分布区域进行对比分析及验证。识别结果与实际水质状况相符,验证了该方法的有效性。 相似文献
89.
土壤质地类型反映了不同粒径颗粒在土壤中的分布,是土壤的最基本性质之一,直接影响土壤中水、气、热和溶质的迁移特征,因此确定土壤质地类型是土壤调查中最基础的工作。我国常用的土壤质地分类标准有美国制、国际制、卡庆斯基制和中国制标准,其中美国制和国际制土壤质地分类需借助平面三角坐标系来确定,不利于批量土壤样品的土壤质地分类。现有的土壤质地自动分类系统中缺少基于卡庆斯基制、中国制的分类功能,且难以直接处理激光粒度仪的测试结果。为能够批量自动实现土壤质地分类并便于不同分类制结果的对比,基于MATLAB GUI开发了土壤质地类型自动识别系统(GSTARS)。该系统界面直观、操作方便,能够批量处理土壤颗粒测试数据和多种格式数据文件,且数据处理容量大;该系统包含了4种国内应用最广的土壤质地分类标准,增加了系统的适用性,便于不同分类制分类结果的对比。与现有土壤质地分类工具的结果对比,表明本系统的分类结果可靠。 相似文献
90.
为开展区域风险评估,融合手机信令、气象和地理信息等多源数据,引入随机森林机器学习、非参数估计分位数图示法和非监督学习K-mean等方法,构建了区域PM2.5风险评估及特征识别评价框架,在南京市区以0.3km分辨率网格为基础单元开展了案例研究.结果表明,该技术既可有效模拟PM2.5浓度时空分布,十折交叉验证R2达到0.76,证明了准确度较高,并基于此识别出4种主要污染特征;也可有效捕捉短期人口流动导致的风险,在污染浓度不变的情况下短期人口流动会导致风险增加0.30~0.97倍.综合PM2.5浓度和人口分布,识别出4种主要暴露风险模式,其中,研究区域6.5%的面积为高风险地区,23.0%的面积为低风险地区.“十四五”期间应加快现代科学技术在环境保护领域的应用,实施网格化和差异化的风险控制政策,维护人群健康. 相似文献