全文获取类型
收费全文 | 751篇 |
免费 | 63篇 |
国内免费 | 225篇 |
专业分类
安全科学 | 54篇 |
废物处理 | 25篇 |
环保管理 | 64篇 |
综合类 | 470篇 |
基础理论 | 86篇 |
污染及防治 | 159篇 |
评价与监测 | 72篇 |
社会与环境 | 74篇 |
灾害及防治 | 35篇 |
出版年
2024年 | 6篇 |
2023年 | 24篇 |
2022年 | 37篇 |
2021年 | 36篇 |
2020年 | 37篇 |
2019年 | 28篇 |
2018年 | 22篇 |
2017年 | 26篇 |
2016年 | 37篇 |
2015年 | 41篇 |
2014年 | 46篇 |
2013年 | 80篇 |
2012年 | 61篇 |
2011年 | 76篇 |
2010年 | 61篇 |
2009年 | 48篇 |
2008年 | 60篇 |
2007年 | 54篇 |
2006年 | 42篇 |
2005年 | 32篇 |
2004年 | 29篇 |
2003年 | 31篇 |
2002年 | 25篇 |
2001年 | 32篇 |
2000年 | 21篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有1039条查询结果,搜索用时 15 毫秒
41.
对2种氰化物显色剂配制方法进行了对比,发现用无水乙醇配制的显色剂具有方便,经济,实用,无毒且显色剂保存期长等优势。 相似文献
42.
43.
简述了塔山水库蓝藻暴发的过程及成因。指出 ,由于水库的营养物质增多、水质恶化 ,在不利的水文、气象 (高温、光照充足、微风 )等条件下 ,导致蓝藻暴发。提出了相应的控制对策 相似文献
44.
Jie Liu Junjun Ma Weizhang Zhong Jianrui Niu Zaixing Li Xiaoju Wang Ge Shen Chun Liu 《Frontiers of Environmental Science & Engineering》2023,17(4):51
45.
Soon-Ung Park Moon-Soo Park Youngsin Chun 《Atmospheric environment (Oxford, England : 1994)》2010,44(38):4964-4972
A 20-m Asian dust monitoring tower was installed at Erdene in Dornogobi, Mongolia in later 2008, which is one of the high Asian dust source regions in the Asian domain, to investigate meteorological conditions for the dust events. The tower was equipped with meteorological sensors (temperature, humidity and wind speed at four levels, precipitation and pressure near the surface), radiation sensors (solar radiation, net radiation) and soil measurement sensors (soil moisture and soil temperature at three levels and soil heat flux at one level) and turbulent measurement (sonic anemometer) at the 8 m height and PM10 concentration measurement (beta guage) at the 3 m height. Measurement was made for a full year of 2009. The observed data indicated that dust events occur all year round with the maximum hourly mean maximum concentration of 4107 μg m?3 in the early May to a minimum of 92 μg m?3 in later August. It was found that the dust concentration at this site is directly related to the wind speed exceeding the threshold wind speed (likewise the corresponding friction velocity) during the winter to early spring. However, the observed dust concentration is not only related to the wind speed exceeding the threshold wind speed but also to the Normalized Difference Vegetation Index (NDVI) during the late spring to the late autumn due to the growth of vegetation. It was also found that the surface soil moisture content does not affect the dust concentration due to the relatively short residence time of the soil moisture in the surface soil. The presently monitored data can be used to verify parameters used in the Asian Dust Aerosol Model (ADAM) that is the operational forecasting dust model in the Korea Meteorological Administration (KMA). 相似文献
46.
20 0 1 0 1 2 6印度西北部的普杰地区发生了 7 8级强烈地震。对这次强震事件 ,利用卫星遥感监测地气系统射出长波辐射的数值产品资料 ,分析了以普杰为中心整个西亚范围内 ,事件发生前后共计 6个月的月平均辐射场的分布特征及其演变过程。发现自震前 2个月至震时当月 ,普杰地区始终是一个辐射 (热 )场的高值中心 ,震后明显消散。据此认为印度大地震有可识别的预警信息 ,提出利用卫星遥感技术及其产品 ,有可能为“突破”短临地震预报开拓出一种新的预测技术生长点 相似文献
47.
差异性区域网格化环境管理是在环境状况存在明显分异区域进行环境管理的有效的方式。依托网格化管理在资源整合和信息共事方面的优势.探讨在环境状况差异明显区域构建网格化管理体系的目标、步骤与管理思路。以上海市宝山区的实践为例.根据区内环境现状差异明显的特征。将全区划分为150个网格.从中选取环境矛盾较为突出的网格.开展区域环境综合整治与环境建设.逐年逐块提升区域网格环境状况.实现区域环境网格等级的提升.初步达成区域生态、生产、生活的协调。实践表明.差异性区域网格化管理是建设环境友好型社会的一种有效的环境管理手段。 相似文献
48.
49.
This research aimed to investigate the interspecific and intraspecific identification of Dendrobium by using the multi-locus method so as to provide a molecular basis for Dendrobium identification through the combination of chloroplast psbA-trnH intergenic region sequences and ribosome 5S rRNA gene spacer sequences. PCR direct sequencing was applied to detect the chloroplast psbA-trnH intergenic region sequences as well as the ribosome 5S rRNA gene spacer sequences of 12 Dendrobium species, while the psbA-trnH intergenic region sequences of Dendrobium denneanum dq-2 variety and dq- 5line were cloned and sequenced for single nucleotide polymorphism (SNP) analyzing. The sequences were analyzed by the software Sequencher4.14, Bioedit7.0, MEGA5.2 and Dansp5.0; the interspecific and intraspecific Kimara-2-Parameter(K2P) distances were also calculated. The phylogenetic tree (using Neighbor joining method) was constructed with Bulbophyllum odoratissimum and Bletilla striata as outgroup. The results showed an average length of chloroplast psbA-trnH gene sequences in Dendrobium as 742.3 bp, with 72 variable sites, including 33 information sites; the average length of the ribosome 5S rRNA gene spacer sequences in Dendrobium was 336.4 bp, with 213 variable sites including 139 information sites. Using psbAtrnH intergenic region sequences in combination with ribosome 5S rRNA gene spacer sequences can not only identify D. denneanum, D. hancockil, D. thysiflorum, D. devonianum, D. moniliforme, D. chrysotoxum, D. officinale, D. heterocarpum and D. nobile, but also differentiate D. officinale from different geographical populations, and distinguish the dq-2 variety and dq 5line with SNP in the multi locus of D. denneanum. 相似文献
50.
通过定位监测和样品跟踪采集,在旱季对喀斯特小流域连续20天无前期降雨的一场暴雨(累计降雨量64mm)水文水化学过程进行了动态监测,并分析了相关的影响因素。结果表明,小降雨事件(8.5mm)未能引起溪流水位、电导率及温度的明显变化,而当累计降雨量达到35.5mm后溪流水开始响应。此后,溪流水文水化学参数对降雨快速响应,除硝态氮外,电导率(EC)、δ18 O、Ca2+迅速降至最低值,雨水稀释作用对其水化学变化起主要作用。通过对溪流新旧水比例进行划分发现,降雨前期和后期,溪流以旧水补给为主,而在水位快速上涨阶段,新水比例达到34%左右。两次降雨过程中,在溪流水水位升高的情况下,水体中硝态氮浓度仍然表现出高于雨前浓度的趋势。该研究为该区旱季小流域水资源利用和污染物防治方面提供了一定理论依据。 相似文献