全文获取类型
收费全文 | 23215篇 |
免费 | 5123篇 |
国内免费 | 28755篇 |
专业分类
安全科学 | 2290篇 |
废物处理 | 1053篇 |
环保管理 | 2045篇 |
综合类 | 35519篇 |
基础理论 | 4184篇 |
环境理论 | 3篇 |
污染及防治 | 8266篇 |
评价与监测 | 2031篇 |
社会与环境 | 770篇 |
灾害及防治 | 932篇 |
出版年
2024年 | 38篇 |
2023年 | 308篇 |
2022年 | 859篇 |
2021年 | 765篇 |
2020年 | 1273篇 |
2019年 | 2282篇 |
2018年 | 2533篇 |
2017年 | 2657篇 |
2016年 | 2330篇 |
2015年 | 2899篇 |
2014年 | 3653篇 |
2013年 | 4069篇 |
2012年 | 3840篇 |
2011年 | 3426篇 |
2010年 | 3003篇 |
2009年 | 3016篇 |
2008年 | 2762篇 |
2007年 | 2579篇 |
2006年 | 2023篇 |
2005年 | 1549篇 |
2004年 | 1338篇 |
2003年 | 1133篇 |
2002年 | 962篇 |
2001年 | 927篇 |
2000年 | 1037篇 |
1999年 | 880篇 |
1998年 | 690篇 |
1997年 | 646篇 |
1996年 | 661篇 |
1995年 | 565篇 |
1994年 | 370篇 |
1993年 | 310篇 |
1992年 | 359篇 |
1991年 | 317篇 |
1990年 | 259篇 |
1989年 | 207篇 |
1988年 | 150篇 |
1987年 | 75篇 |
1986年 | 79篇 |
1985年 | 56篇 |
1984年 | 55篇 |
1983年 | 43篇 |
1982年 | 46篇 |
1981年 | 35篇 |
1978年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1972年 | 7篇 |
1971年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
11.
Wu You Liu Zhuannian Bakhtari Mohammad Fahim Luo Junnan 《Environmental science and pollution research international》2021,28(37):51404-51404
Environmental Science and Pollution Research - A Correction to this paper has been published: https://doi.org/10.1007/s11356-021-15526-6 相似文献
12.
Processes involved in uptake and release of nitrogen dioxide from soil and building stones into the atmosphere 总被引:1,自引:0,他引:1
Atmospheric NO2 was taken up by samples of various soils and building stones. The NO2 uptake rate constants were highest in soil samples taken during the summer months. However, the NO2 uptake rate constants of the soils and building stones were not significantly correlated with any of the following variables: moisture, pH, ammonium, nitrite, or nitrate. NO2 uptake by soil and stone was not abolished by autoclaving indicating a chemical uptake process. NO2 uptake by acidic and air-dry soils and stones resulted in nearly stoichiometric reduction of NO2 to NO. This reduction was enhanced by the addition of ferrous iron and was further enhanced by incubation under 1 ppmv SO2. The results suggest that NO2 reduction may be coupled to oxidation of ferrous to ferric iron which may be reduced again by atmospheric SO2 thus regenerating the ferrous iron content of the soil or stone. Conversion of NO2 to NO was not observed in neutral or/and moist soils and stones. NO2 was also taken up by purified and sterilized quartz sand moistend with water. This uptake was enhanced by addition of humic material but not by addition of bacteria which both had been extracted from genuine soil. Under most conditions, only uptake but no release of NO2 was observed. However, NO2 was released in air-dry soils that were heated to 45–65°C, or in ammonium-fertilized soil or stone that was drying up at room temperature. Under the latter conditions mimicking field practice, the NO2 release reached rates that were similar to the NO release rates. 相似文献
13.
记者:卢局长您好!深圳市安全生产监督管理局今天成立了,请您向广大读者介绍一下这个新机构的主要职能有哪些? 卢局长:今天是一个非常重要的日子,深圳市安全生产监督管理局正式揭牌运作,《中华人民共和国安全生产法》也于今天开始实施。按照市机构编制委员会文件的规定,新成立的市安监局主要承担八项职责。概括起来讲,这些职责主要是组织贯彻国家有关安 相似文献
14.
各位理事、各位来宾、同志们、朋友们: 为期三天的中国安全防范产品行业协会第三届第三次理事(扩大)会议,完成了各项预定议程,顺利结束. 相似文献
15.
长江流域的昆虫病毒资源及其开发利用 总被引:1,自引:0,他引:1
在长江流域已发现约130种昆虫病毒,其中多数属杆状病毒科。昆虫病毒作为杀虫剂在本地区广泛应用,防治棉花、森林、茶树、蔬菜和牧草上的害虫,克服了化学农药的一些缺点,取得了良好的生态效益和经济效益。近年来还进行了杆状病毒表达载体的研究,该系统的研制已用于高水平表达具有生物活性的外源基因产物,获得医药产品,或者组建更有效的基因工程病毒杀虫剂。 相似文献
16.
We report on the prenatal diagnosis of ring chromosome 15 in a fetus with increased nuchal fold and intrauterine growth restriction (IUGR). A 27-year-old woman gravida 2, para 1 had normal maternal serum screen tests in the early second trimester of the index pregnancy. Fetal nuchal fold thickening up to 8 mm was incidentally found during the routine obstetric ultrasound scan at 20 weeks' gestation. Amniocentesis was undertaken and the fetal karyotype was found to be 46,XY,r(15) on cytogenetic study. Fluorescence in situ hybridization (FISH) using a telomeric probe of chromosome 15 demonstrated a terminal deletion on the q arm of the ring-shaped chromosome 15. This is the first report of a prenatally diagnosed case of ring chromosome 15. Moreover, nuchal fold thickness in the second trimester may have a role in its prenatal diagnosis. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
17.
广州轨道交通三号线高速行驶条件下对安全限界的影响研究 总被引:3,自引:2,他引:1
给出了轨道交通车辆横向偏移量的计算方法 ,并应用列车 -线路动力耦合模型 ,分析了广州地铁三号线的安全限界变化问题。确定了当前按 80km/h行车速度设计的建筑限界能满足 13 0km/h行车速度的要求 ,限界尺寸不需改动可保证列车运行安全平稳 相似文献
18.
通过滇池鲤鱼与松花坝水库和国内外同类鲤鱼的元素含量对比,确认滇池鲤鱼受工业污水的危害影响主要是As、Se。鱼体As、Se含量目前已经超过正常值,Ni、Cr、Cu、Fe、Pb比正常值偏低,其它元素属正常值范围。为了避免过多的元素富集,建议滇池鲤鱼以半年到一年为生长捕捞期为宜。 相似文献
19.
南宁城市大气污染对人体健康的危害及治理对策 总被引:6,自引:0,他引:6
南宁市大气属煤烟型污染 ,大气的主要污染物为SO2 、NOx、TSP、降尘 ,虽然随着环境管理和污染治理工作的加强 ,污染物浓度逐年下降 ,但是工业区大气污染仍然较重。污染物流行病学调查显示 :工业区癌症和呼吸系统疾病死亡率均高于全市平均水平 2倍左右 ,城区又高于郊区 2倍 ,大气污染综合指数与呼吸内科门诊就诊人数呈正相关。用邓聚龙的灰色系统理论分析得知污染物对癌症和呼吸系统疾病死亡率有关联 ,关联度从大到小排序为 :TSP >降尘 >SO2 >NOx ,最后提出了大气污染治理的对策。 相似文献
20.
The alpine musk deer (Moschus chrysogaster) is a key species of some terrestrial ecosystems, it has an important economic and conservative significance as a kind of medical animal in China. Due to the interaction between natural forces and human disturbance, the habitats of alpine musk deer are fragmented and isolated in different mountains and the populations are confronted with many problems of survival. In this paper, we discuss the impact of habitat fragmentation and isolation on alpine musk deer populations based on the investigation on the population densities and sizes and environmental factors in different reserves, as well as on the analysis of its ecological adaptability. We found that the alpine musk deer has strong ecological adaptability; the population development of alpine musk deer may benefit from the reduction of the forest area and even from the fragmentation and isolation of the habitat to a certain extent. However, deforestion should not be encouraged only for the alpine musk deer population, but should also be based on the overall consideration of biodiversity conservation. 相似文献