全文获取类型
收费全文 | 900篇 |
免费 | 68篇 |
国内免费 | 285篇 |
专业分类
安全科学 | 64篇 |
废物处理 | 37篇 |
环保管理 | 64篇 |
综合类 | 744篇 |
基础理论 | 157篇 |
污染及防治 | 138篇 |
评价与监测 | 39篇 |
社会与环境 | 8篇 |
灾害及防治 | 2篇 |
出版年
2024年 | 9篇 |
2023年 | 26篇 |
2022年 | 28篇 |
2021年 | 58篇 |
2020年 | 36篇 |
2019年 | 34篇 |
2018年 | 30篇 |
2017年 | 27篇 |
2016年 | 37篇 |
2015年 | 39篇 |
2014年 | 78篇 |
2013年 | 48篇 |
2012年 | 32篇 |
2011年 | 62篇 |
2010年 | 51篇 |
2009年 | 48篇 |
2008年 | 55篇 |
2007年 | 58篇 |
2006年 | 53篇 |
2005年 | 36篇 |
2004年 | 48篇 |
2003年 | 36篇 |
2002年 | 42篇 |
2001年 | 43篇 |
2000年 | 48篇 |
1999年 | 25篇 |
1998年 | 26篇 |
1997年 | 27篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 19篇 |
1993年 | 13篇 |
1992年 | 19篇 |
1991年 | 16篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 1篇 |
排序方式: 共有1253条查询结果,搜索用时 15 毫秒
991.
中国肝癌与土壤环境中化学元素的相关性研究 总被引:13,自引:1,他引:13
利用土壤元素资料2069448个数据,肝癌死亡调查资料121080例,研究了肝癌死亡率与土壤环境中64个元素的相关性。结果表明,64个元素中有18种元素的与肝癌死亡率有关,同时得到了相应的等级相关系数。 相似文献
992.
993.
采用盆栽模拟试验,对汞(Hg)及甲基汞(MeHg)在酸性紫色水稻土中不同水稻生长期的动态变化进行了研究,并分析对比了总汞(THg)和MeHg在水稻体中的富集特征.结果表明:在水稻生长期间,土壤总汞含量变化较小,MeHg含量随时间增加而增加,土壤MeHg/THg值的变化趋势和土壤中MeHg含量变化一致.完熟期THg在水稻中植株的分布状况为:根籽粒茎叶穗壳,MeHg的分布为:籽粒根茎叶穗壳.水稻植株中MeHg/THg均值为24.03%,大于土壤均值3.05%,说明水稻植株中具有较强的MeHg累积能力.在水稻生长周期内,水稻体内MeHg富集系数均值为8.16,远大于THg富集系数的均值2.31,且籽粒中的MeHg富集系数大于根、茎、叶,说明水稻对MeHg的富集能力强于THg,且籽粒更易于富集MeHg.水稻体内的MeHg的转移系数大于THg,且籽粒中MeHg的转移系数大于1,进一步说明MeHg比THg更易在水稻体内转移. 相似文献
994.
Effect of alginic acid decomposing bacterium on the growth of Laminaria japonica (Phaeophyceae) 总被引:1,自引:0,他引:1
We collected the diseased blades of Larninaria japonica from Yantai Sea Farm from October to December 2002, and the alginic acid decomposing bacterium on the diseased blade was isolated and purified, and was identified as A lteromonas espejiana. This bacterium was applied as the causative pathogen to infect the blades of L. japonica under laboratory conditions. The aim of the present study was to identify the effects of the bacterium on the growth of L. japonica, and to find the possibly effective mechanism. Results showed that: (1)The blades of L.japonica exhibited symptoms of lesion,bleaching and deteriortion when infected by the bacterium. and their growth and photosynthesis were dramatically suppressed. At the same time, the reactive oxygen species (ROS) generation enhanced obviously, and the relative membrane permeability increased significantly. The contents of malonaldehyde (MDA) and free fatty acid in the microsomol membrane greatly elevated, but the phospholipid content decreased. Result suggested an obvious peroxidation and deesterrification in the blades of L. japonica when infected by the bacterium. (2) The simultaneous assay on the antioxidant enzyme activities demonstrated that superoxide dismutase (SOD) and catalase (CAT) increased greatly when infected by the bacterium, but glutathione peroxidase (Gpx) and ascorbate peroxidase (APX) did not exhibit active responses to the bacterium throughout the experiment. (3) The histomorphological observations gave a distinctive evidence of the severity of the lesions as well as the relative abundance in the bacterial population on the blades after infection. The bacterium firstly invaded into the endodermis of L. japonica and gathered around there, and then resulted in the membrane damage, cells corruption and ultimately, the death of L. japonica. 相似文献
995.
土壤脲酶和脱氢酶对活性X-3B红污染暴露的耐受性及机理研究 总被引:4,自引:1,他引:4
采用微宇宙实验方法,研究了棕壤、褐土、红壤等3种我国典型土壤中脲酶和脱氢酶对染料活性X-3B红污染的耐受性及其机理.实验结果表明,3种土壤中的脲酶和脱氢酶活性在试验较低浓度的活性X-3B红污染的环境中均被促进,但被促进的程度有所差异,具体表现为棕壤脲酶活性被促进的效果最为明显,其次红壤,褐土最弱;较低浓度的活性X-3B红污染对褐土脱氢酶活性的促进作用最强,其次红壤,棕壤最弱.3种土壤的脲酶和脱氢酶活性被促进的效果随着时间的推移逐渐减弱.3种土壤的脲酶和脱氢酶活性对高浓度的活性X-3B红污染并没有显示受抑制的趋势.相反,二者基本维持在未受染料活性X-3B红污染的对照土壤的活性水平.因此可以初步认为,土壤脲酶和脱氢酶对染料活性X-3B红的污染暴露毒性有耐受作用.基于实验结果,还就2种酶对活性X-3B红污染暴露的耐受机理进行了分析与探讨. 相似文献
996.
复合硫杆菌生物浸出污泥中重金属的效果及与pH和ORP的关系 总被引:7,自引:2,他引:7
利用复合嗜酸性硫杆菌(氧化硫硫杆菌和氧化亚铁硫杆菌)在不同接种量下(5%,10%,20%)对城市污泥进行生物沥浸,探讨了沥浸过程中不同重金属的浸出效果及其与pH值和氧化还原电位(ORP)的相关关系.结果表明,该方法能有效地浸出污泥中的重金属,生物沥浸处理10d后.污泥中Cu、Zn和Ni的浸出率可分别达到98%、99%和90%,硫杆菌接种量越大,沥浸反应速率越快,20%接种处理10%接种处理5%接种处理未接种处理.污泥生物沥浸过程中pH的下降和ORP的上升,是促进污泥重金属溶出的主要驱动力,但其中Cu的浸出同时受pH下降和ORP上升的双重影响,而zn和Ni的浸出则主要受pH影响.污泥中Cu、Zn和Ni开始大幅度浸出的pH阈值大约为4、5和5左右.研究还发现,生物沥浸处理虽可使污泥中有机质、全氮、全磷和全钾含量有所下降,但并不影响其农业利用价值. 相似文献
997.
Bi2WO6可见光催化降解染料废水实验研究 总被引:1,自引:0,他引:1
采用水热法合成了新型的可见光催化剂Bi2WO6,以活性蓝M-2GE染料废水为目标污染物,研究了催化剂的用量、污染物初始浓度、溶液pH、盐效应等因素对光催化降解效果的影响.结果表明,在优化实验条件下(催化剂的投加量为3g·L-1、pH值中性偏酸性、反应90min),对目标污染物的去除率可达到99%;溶液中盐浓度的增加对降解有抑制作用;催化剂对不同初始浓度活性蓝M-2GE染料的去除过程遵循一级动力学方程;催化剂重复使用后催化效果有所下降,但仍然可以保持在90%左右.因此,用水热法合成的催化剂Bi2WO6具有良好的可见光活性. 相似文献
998.
999.
1000.
Mineral materials as feasible amendments to stabilize heavy metals
in polluted urban soils 总被引:2,自引:0,他引:2
Four minerals, agricultural limestone (AL), rock phosphate (RP), palygorskite (PG), and calcium magnesium phosphate (CMP),
were evaluated by means of chemical fractions of heavy metals in soils and concentrations of heavy metals in leachates from columns
to determine their ability to stabilize heavy metals in polluted urban soils. Two urban soils (calcareous soil and acidic soil) polluted
with cadmium, copper, zinc and lead were selected and amended in the laboratory with the mineral materials) for 12 months. Results
indicated that application of the mineral materials reduced exchangeable metals in the sequence of Pb, Cd > Cu > Zn. The reduction of
exchangeable fraction of heavy metals in the soils amended with di erent mineral materials followed the sequence of CMP, PG > AL
> RP. Reductions of heavy metals leached were based on comparison with cumulative totals of heavy metals eluted through 12 pore
volumes from an untreated soil. The reductions of the metals eluted from the calcareous soil amended with the RP, AL, PG and CMP
were 1.98%, 38.89%, 64.81% and 75.93% for Cd, 8.51%, 40.42%, 60.64% and 55.32% for Cu, 1.76%, 52.94%, 70.00% and 74.12%
for Pb, and 28.42%, 52.74%, 64.38% and 49.66% for Zn. Those from the acidic soil amended with the CMP, PG, AL, and RP were
25.65%, 68.06%, 78.01% and 79.06% for Cd, 26.56%, 49.64%, 43.40% and 34.68% for Cu, 44.44%, 33.32%, 61.11% and 69.44%
for Pb, and 18.46%, 43.77%, 41.98% and 40.68% for Zn. The CMP and PG treatments were superior to the AL and RP for stabilizing
heavy metals in the polluted urban soils. 相似文献