首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3556篇
  免费   318篇
  国内免费   1237篇
安全科学   506篇
废物处理   141篇
环保管理   260篇
综合类   2269篇
基础理论   542篇
污染及防治   816篇
评价与监测   163篇
社会与环境   213篇
灾害及防治   201篇
  2024年   12篇
  2023年   73篇
  2022年   219篇
  2021年   223篇
  2020年   208篇
  2019年   154篇
  2018年   186篇
  2017年   207篇
  2016年   192篇
  2015年   259篇
  2014年   254篇
  2013年   361篇
  2012年   289篇
  2011年   318篇
  2010年   237篇
  2009年   210篇
  2008年   230篇
  2007年   220篇
  2006年   166篇
  2005年   147篇
  2004年   103篇
  2003年   125篇
  2002年   124篇
  2001年   106篇
  2000年   99篇
  1999年   74篇
  1998年   58篇
  1997年   66篇
  1996年   39篇
  1995年   37篇
  1994年   32篇
  1993年   28篇
  1992年   16篇
  1991年   10篇
  1990年   10篇
  1989年   5篇
  1988年   6篇
  1987年   4篇
  1983年   1篇
  1981年   1篇
  1972年   1篇
  1931年   1篇
排序方式: 共有5111条查询结果,搜索用时 15 毫秒
121.
122.
Environmental Science and Pollution Research - Groundwater pollution seriously threatens water resource safety due to high-intensity land use throughout the world. However, the relationship between...  相似文献   
123.

Waterpipe (aka hookah) tobacco smokers are exposed to toxicants that can lead to oxidative DNA and RNA damage, a precursor to chronic disease formation. This study assessed toxicant exposure and biomarkers of DNA [8-oxo-7, 8-dihydro-2′-deoxyguanosine (8-oxodG)] and RNA [8-oxo-7,8-dihydroguanosine (8-oxoGuo)] oxidative damage during smoking of flavored and non-flavored waterpipe tobacco. Thirty waterpipe smokers completed two counterbalanced 2-h lab waterpipe smoking sessions (flavored vs. non-flavored waterpipe tobacco). Urinary concentrations of 8-oxodG and 8-oxoGuo and expired carbon monoxide (eCO) were measured before and after the smoking sessions. A significant increase in the urinary concentrations of 8-oxodG (from 2.12 ± 0.83 to 2.35 ± 0.91 ng/mg creatinine, p = 0.024) and 8-oxoGuo (from 2.96 ± 0.84 to 3.45 ± 0.76 ng/mg creatinine, p = 0.003) were observed after smoking the non-flavored and flavored waterpipe tobacco, respectively. Our results also showed that the mean ± SD of eCO increased significantly after smoking the flavored (from 1.3 ± 1.1 to 20.3 ± 23.6 ppm, p < 0.001) and non-flavored waterpipe tobacco (from 1.8 ± 1.2 to 24.5 ± 26.1 ppm, p < 0.001). There were no significant differences in the means of 8-oxodG (p = 0.576), 8-oxoGuo (p = 0.108), and eCO (p = 0.170) between the flavored and non-flavored tobacco sessions. Smoking non-flavored and flavored waterpipe tobacco leads to oxidative stress and toxicant exposure. Our findings add to the existing evidence about the adverse effects of waterpipe tobacco smoking (WTS) and the need for strong policies to inform and protect young people from the risks of WTS.

  相似文献   
124.
Environmental Science and Pollution Research - Magnetic nanostructured MnFe2O4 with different morphologies, synthesized via chemical co-precipitation and hydrothermal method, was assayed as...  相似文献   
125.
Environmental Science and Pollution Research - Bio-waste materials from aquatic species are alternative sources of chitin and chitosan—high-value natural biodegradable and biocompatible...  相似文献   
126.
Environmental Science and Pollution Research - Co3O4 nanorods with diameters of ~0.15 μm and lengths of ~1 μm were prepared using a hydrothermal method via the assembly of microcrystals...  相似文献   
127.
Environmental Science and Pollution Research - There is a delayed (lag 1 to 2&nbsp;days) correlation between acute PM 2.5 (particulate matter &lt;?2.5&nbsp;μm in aerodynamic...  相似文献   
128.
Environmental Science and Pollution Research - To understand rural sustainability, it is necessary to scrutinize the relationship between rural transition and economic growth. The article uses...  相似文献   
129.
Environmental Science and Pollution Research - The high NO2/NOX ratio in the after-treatment system is beneficial to its performance and achieved by NO catalytic conversion in diesel oxidation...  相似文献   
130.
通过对临沂市全区表层土壤每36 km2进行样品收集,测试分析了DDTs、Org C、N等指标,主要研究了区域表层土壤DDTs的残留现状、组成和来源、影响因素、空间分布和环境质量特征.结果表明,调查区表层土壤中DDTs检出率为71.75%,平均含量为0.035μg·g-1;检出样品中p,p'-DDT和p,p'-DDE为主要残留物,平均残留分别为0.033μg·g-1和0.010μg·g-1,分别占检出样的60.99%和34.62%.DDTs降解率指示区域58%表层土壤为新近输入区,新近输入区在调查区中南部分布尤为明显;而p,p'-DDD/p,p'-DDE指示区域DDTs降解以氧化环境为主,o,p'-DDT/p,p'-DDT指示71.37%区域土壤DDTs输入可能与工业级DDTs有关.相关分析表明,影响土壤DDTs分布的外在因素包括土壤Org C、N、C和p H等指标,且DDTs中p,p'-DDT组分占比越高,影响越明显.DDTs的空间分布具明显点源特征,市县周围均出现明显浓集中心,中南部部分区域浓度明显较高.全区DDTs土壤环境质量污染程度较低,主要以一二类土壤为主,分别占78.95%和21.05%.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号