全文获取类型
收费全文 | 302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 | 15篇 |
综合类 | 87篇 |
基础理论 | 109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 | 6篇 |
灾害及防治 | 15篇 |
出版年
2024年 | 2篇 |
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 14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 | 14篇 |
2009年 | 30篇 |
2008年 | 23篇 |
2007年 | 22篇 |
2006年 | 19篇 |
2005年 | 15篇 |
2004年 | 21篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 7篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有346条查询结果,搜索用时 15 毫秒
91.
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
92.
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
93.
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
94.
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
95.
96.
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
97.
地下水主要组分水化学异常识别方法对比:以柳江盆地为例 总被引:3,自引:1,他引:2
地下水化学组分的异常识别是构建水化学背景值及开展人类活动影响程度识别量化的重要基础.以往提出的基于5种水化学图的主要组分异常识别方法取得了良好效果,但是该方法考虑的水化学图种类过多,计算复杂.为简化水化学图法,本文以柳江盆地为例,尝试采用Durov图替代5种水化学图,对地下水主要组分进行异常识别.为此,分别对比分析了水化学图与数理统计法组合出的7种异常识别方法的剔除效果,并进行方法可靠性检验.结果表明,数理统计法与水化学图法结合识别地下水异常相对于两者单独使用可以取得更好的识别效果;其中3σ准则+5种水化学图法和3σ准则+Durov图法对地下水主要组分异常识别效果最好;并证实采用Durov图可以有效替代5种水化学图进行地下水主要组分的异常识别,既保留了水化学识别异常的科学性,又大大简化了异常识别计算的过程. 相似文献
98.
99.
100.
空气质量综合评价的基于熵权的属性识别模型 总被引:1,自引:0,他引:1
文章通过将熵值法与属性识别模型相结合,建立了基于熵权的属性识别模型来进行空气质量综合评价,从而避免了权重确定的主观性问题。并结合实际说明了建模过程,得出了更符合实际的评价结果。 相似文献