全文获取类型
收费全文 | 894篇 |
免费 | 87篇 |
国内免费 | 215篇 |
专业分类
安全科学 | 80篇 |
废物处理 | 59篇 |
环保管理 | 68篇 |
综合类 | 476篇 |
基础理论 | 164篇 |
环境理论 | 1篇 |
污染及防治 | 211篇 |
评价与监测 | 71篇 |
社会与环境 | 34篇 |
灾害及防治 | 32篇 |
出版年
2024年 | 3篇 |
2023年 | 21篇 |
2022年 | 63篇 |
2021年 | 62篇 |
2020年 | 58篇 |
2019年 | 56篇 |
2018年 | 41篇 |
2017年 | 61篇 |
2016年 | 50篇 |
2015年 | 61篇 |
2014年 | 55篇 |
2013年 | 89篇 |
2012年 | 68篇 |
2011年 | 69篇 |
2010年 | 54篇 |
2009年 | 55篇 |
2008年 | 53篇 |
2007年 | 43篇 |
2006年 | 38篇 |
2005年 | 36篇 |
2004年 | 36篇 |
2003年 | 32篇 |
2002年 | 26篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有1196条查询结果,搜索用时 15 毫秒
951.
Introduction Sincea 7.9MsearthquaketookplaceinManiinSeptember 1997,noshallow focusearthquakesabove 7MshaveattackedtheChinesemainlandinthepastfew years.Thestrongestshallow focusearthquakein 1999reachedonly 5 .6Msandthatin 2 0 0 0was6 .6Ms.Therewerejustthreeearthquakesre… 相似文献
952.
Five municipal sewers with small flow rates (Manarola, Riomaggiore, Portovenere, Tellaro, Bocca di Magra) were studied using the Microtox® test and a bacterial luminescence bioassay in order to evaluate the water quality in these areas of the eastern Ligurian coast. The work was performed including chemical analysis, microbiological and ecotoxicological assays. Analyses were carried out on both the effluents and the water body close to the pipe discharge. None of the measured chemical parameters exceeded the permitted limits, both in the effluents and in the seawater samples, even if some slightly critical situations were highlighted by the Microtox® test on the effluents. On the other hand, the Microtox® appeared to be less effective than another ecotoxicological assay based on the luminescent fraction of epibacteria for the evaluation of seawater quality. The good water quality of the considered areas was assessed although a slightly worse condition was encountered in Bocca di Magra. 相似文献
953.
G. Bestetti E. Collina P. Di Gennaro M. Lasagni D. Pitea 《Water, Air, & Soil Pollution: Focus》2003,3(3):223-231
The research was focused on the slurry-phase biodegradation of naphthalene. The biodegradation process was optimised with preliminary experiments in slurry aerobic microcosms. From soil samples collected on a contaminated site, a Pseudomonas putida strain, called M8, capable to degrade naphthalene was selected. Microcosms were prepared with M8 strain by mixing non-contaminated soil and mineral M9 medium. Different experimental conditions were tested varying naphthalene concentration, soil:water ratio and inoculum density. The disappearance of hydrocarbon, the production of carbon dioxide, and the ratio of total heterotrophic and naphthalene-degrading bacteria were monitored at different incubation times. The kinetic equation that best fitted the disappearance of contaminant with time was determined. The results showed that the isolated strain enhanced the biodegradation rate with respect to the natural biodegradation. 相似文献
954.
Alfredo Nazzaro Matteo Della Monica Fortunato Lonardo Arturo Di Blasi Maria Baffico Maurizia Baldi Giovanni Nazzaro Giuseppe De Placido Gioacchino Scarano 《黑龙江环境通报》2004,24(11):918-922
Pfeiffer syndrome is characterized by bilateral coronal craniosynostosis, midface hypoplasia, beaked nasal tip, broad and medially deviated thumbs and great toes. Originally, it was described in eight persons from three generations in a pedigree consistent with an autosomal dominant transmission. Since then, several reports have documented its high clinical and genetic heterogeneity. The condition is usually detected in the newborn period or later, and very few prenatal ultrasound diagnoses have been reported. We present a case of Pfeiffer syndrome prenatally diagnosed at 20 weeks' gestation, in which the sonographic features of craniosynostosis, hypertelorism associated with an extreme proptosis, and broad thumb led to the diagnosis, confirmed after termination of pregnancy by dysmorphological, pathological and radiological evaluation. DNA analysis of the fibroblast growth factor receptor 2 (FGFR2) showed a missense mutation consisting in a transversion G → C at nucleotide 870. This led to a Trp290Cys amino acidic substitution. We discuss the relevant findings of our and previously published cases. Our report demonstrates that a careful sonographic examination can lead to an early prenatal diagnosis of Pfeiffer syndrome also in cases without cloverleaf skull. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
955.
956.
Matteo Della Monica Alfredo Nazzaro Fortunato Lonardo Gerardo Ferrara Arturo Di Blasi Gioacchino Scarano 《黑龙江环境通报》2005,25(5):394-397
A case of cloacal exstrophy (CE) was detected by ultrasound as early as 22 weeks of gestation in association with myelocystocele complex, an unusual form of occult spinal dysraphism often associated with such a disease. The ultrasonographic diagnosis was made through the detection of a wavy cord-like segment of soft tissue protruding from the anterior abdominal wall, just below the umbilical cord insertion, strongly resembling the trunk of an elephant. Our article enforces the suggestion that the ultrasound elephant trunk–like image should be added to the existing major criteria for making prenatal diagnosis of CE. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
957.
采用走航连续观测系统分别在2011年5月和2015年5月对南海北部表层水体温度、盐度、溶解氧、叶绿素a和pCO_2进行了现场观测.在El Nio影响下,2015年5月华南地区及广东省降雨量偏多,大量冲淡水入海,南海北部冲淡水区域海表盐度显著降低,2015年5月冲淡水区域海表盐度平均值为(28.05±6.18),低于2011年5月的海表盐度平均值(29.65±2.58),同时实测冲淡水区域海表温度平均升高约2.10℃.冲淡水携带的营养物质和适度升高的海表温度共同促进了冲淡水区域浮游植物的繁殖.浮游植物光合作用不断地将海水中的游离CO2转化为有机碳,同时释放出氧气,使得水体pCO_2降低,2015年5月冲淡水区域pCO_2平均值为(286±95)μatm,低于2011年5月的pCO_2平均值(300±42)μatm.2015年5月实测获得离岸海域pCO_2平均值为(421±9)μatm,高于2011年5月pCO_2平均值(386±13)μatm,二者差值为35μatm,海表温度是离岸海域pCO_2的主要影响因子,2015年5月El Nio期间离岸海域SST升高1.96℃.El Nio影响下冲淡水区域的碳汇作用增加,离岸海域的碳源作用增强,冲淡水区域碳汇增加与离岸海域碳源增强基本抵消,2015年5月南海北部整体仍是CO_2弱汇区,约为-0.40 mmol·m~(-2)·d~(-1),与2011年5月通量值-0.58 mmol·m~(-2)·d~(-1)差别不明显. 相似文献
958.
当前,城镇污水处理厂尾水对受纳水体的水质有着不可忽视的影响。以改善湖泊水质为目的,使用仿生组合工艺对尾水进行深度净化研究。结果表明:仿生组合工艺对尾水COD 的降解效率达到42.31%~67.95%,对COD波动具有较高的适应性;仿生组合工艺弥补了仿生填料床对NH3-N、TP的降解具有适应期的缺陷;仿生组合工艺对尾水NH3-N去除率高达89.57%~97.89%;仿生组合工艺强化了对TP的去除率,去除率为53.85%~72.41%,出水TP达到地表水III类水标准;仿生组合工艺SS去除效率达到37.50%~64%。 相似文献
959.
2013年10月至2014年7月,在太原城区,分4个月采集大气细颗粒物,每个月选取4个样品,分析了颗粒物上8种有机磷酸酯阻燃剂(OPFRs)的浓度与组成。结果表明,大气PM2.5样品中OPFRs总浓度算术平均值为890±486 pg/m3,其中三种含氯有机磷阻燃剂(TCEP,TCPP和TDCPP)占总量的80%,其他5种无氯OPFRs占总量的20%。化合物组成上,以TCPP(38.5%)最高,其次分别为TCEP(34.6%)、TPP(9.6%)、TDCPP(6.9%)、TTP(5.1%)、TBP(3.2%)、Eh DPP(1.1%)和TEHP(0.8%)。季节变化来看,夏秋季样品中OPFRs浓度较高,而冬春样品浓度较低,且在化合物组成上,夏秋季样品中含氯OPFRs相对浓度要高于冬春季样品。相关分析显示,有机磷阻燃剂浓度变化与颗粒物浓度、有机质含量高低和环境温度无相关性,而主要与气团来源有关。 相似文献
960.