全文获取类型
收费全文 | 234篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 3篇 |
废物处理 | 12篇 |
环保管理 | 22篇 |
综合类 | 26篇 |
基础理论 | 39篇 |
污染及防治 | 87篇 |
评价与监测 | 34篇 |
社会与环境 | 13篇 |
灾害及防治 | 1篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 10篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 11篇 |
2013年 | 32篇 |
2012年 | 11篇 |
2011年 | 13篇 |
2010年 | 10篇 |
2009年 | 4篇 |
2008年 | 16篇 |
2007年 | 13篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 10篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 6篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 4篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 3篇 |
1964年 | 3篇 |
1963年 | 4篇 |
1962年 | 1篇 |
排序方式: 共有237条查询结果,搜索用时 231 毫秒
101.
A. S. Pipal S. Tiwari P. G. Satsangi Ajay Taneja D.S. Bisht A. K. Srivastava M. K. Srivastava 《Environmental science and pollution research international》2014,21(14):8678-8691
Agra, one of the oldest cities “World Heritage site”, and Delhi, the capital city of India are both located in the border of Indo-Gangetic Plains (IGP) and heavily loaded with atmospheric aerosols due to tourist place, anthropogenic activities, and its topography, respectively. Therefore, there is need for monitoring of atmospheric aerosols to perceive the scenario and effects of particles over northern part of India. The present study was carried out at Agra (AGR) as well as Delhi (DEL) during winter period from November 2011 to February 2012 of fine particulate (PM2.5: d?<?2.5 μm) as well as associated carbonaceous aerosols. PM2.5 was collected at both places using medium volume air sampler (offline measurement) and analyzed for organic carbon (OC) and elemental carbon (EC). Also, simultaneously, black carbon (BC) was measured (online) at DEL. The average mass concentration of PM2.5 was 165.42?±?119.46 μg m?3 at AGR while at DEL it was 211.67?±?41.94 μg m?3 which is ~27 % higher at DEL than AGR whereas the BC mass concentration was 10.60 μg m?3. The PM2.5 was substantially higher than the annual standard stipulated by central pollution control board and United States Environmental Protection Agency standards. The average concentrations of OC and EC were 69.96?±?34.42 and 9.53?±?7.27 μm m?3, respectively. Total carbon (TC) was 79.01?±?38.98 μg m?3 at AGR, while it was 50.11?±?11.93 (OC), 10.67?±?3.56 μg m?3 (EC), and 60.78?±?14.56 μg m?3 (TC) at DEL. The OC/EC ratio was 13.75 at (AGR) and 5.45 at (DEL). The higher OC/EC ratio at Agra indicates that the formation of secondary organic aerosol which emitted from variable primary sources. Significant correlation between PM2.5 and its carbonaceous species were observed indicating similarity in sources at both sites. The average concentrations of secondary organic carbon (SOC) and primary organic carbon (POC) at AGR were 48.16 and 26.52 μg m?3 while at DEL it was 38.78 and 27.55 μg m?3, respectively. In the case of POC, similar concentrations were observed at both places but in the case of SOC higher over AGR by 24 in comparison to DEL, it is due to the high concentration of OC over AGR. Secondary organic aerosol (SOA) was 42 % higher at AGR than DEL which confirms the formation of secondary aerosol at AGR due to rural environment with higher concentrations of coarse mode particles. The SOA contribution in PM2.5 was also estimated and was ~32 and 12 % at AGR and DEL respectively. Being high loading of fine particles along with carbonaceous aerosol, it is suggested to take necessary and immediate action in mitigation of the emission of carbonaceous aerosol in the northern part of India. 相似文献
102.
103.
104.
105.
IntroductionNitrificationisaprocessinwhichammoniumformofnitrogenisconvertedintonitrateform .Nitrogenuseefficiencyintermsofplantuptakeisgenerallylowandvariesgreatlyunderdifferentsoilandcroppingconditions.MostfertilizerNappliedtosoilsisintheformofammonium orammoniumproducingcompoundssuchasurea,andisusuallyoxidizedrapidlytonitratebynitrifyingmicroorganismsinsoils.Applicationofnitrogenfertilizersmorethanoptimumlevelsleadstolownitrogenrecoveriesandgreaternitrogenaccumulationinthesoilprofile .Theac… 相似文献
106.
Saxena A Sharma S Kulshrestha UC Srivastava SS 《Environmental pollution (Barking, Essex : 1987)》1991,74(2):129-138
Rain water was collected and analysed from a reference site, Dayalbagh and Taj Ganj, near the Taj Mahal in Agra. The ionic components Ca, Mg, Na, K, NH(4), Pb, Fe, Zn, SO(4), HCO(3), Cl and F were analysed along with pH, alkalinity and conductance. The average pH of rain water at both sites is 7.05. There is a dominance of alkaline components, particularly Ca. The rain water chemistry shows the importance of calcareous soil-derived materials in controlling the pH of rain water. 相似文献
107.
Khandkar UR Gangwar MS Srivastava PC Singh M 《Environmental pollution (Barking, Essex : 1987)》1993,79(3):297-302
Naturally weathered and unweathered samples of fly ashes produced from Gondwana and lignite coals were characterized for their edaphological properties. The particle size distribution in these fly ashes varied widely, and the percentage of [Formula: see text] size particles governed their water holding capacity. All fly ashes were noncoherent in the dry state and had lower particle density than quartz and mulite. The fly ashes were low in available N, but were sufficient in available P, K, Ca, Mg, S, Cu, Fe, Mn, Zn and B. Among the fly ashes, unweathered lignite fly ash was the richest source of K, Ca, Mg, S and Fe, while weathered lignite fly ash had the highest amounts of Mn, Zn and B. The pH of the fly ashes was closely related to the ratio of exchangeable Ca to exchangeable Al. The fly ashes were high in soluble salt, but were poor in cation exchange capacity. As an amendment to correct soil pH, the fly ashes had a poor buffering capacity. Weathering decreased the total Fe, available S and exchangeable Na percentages, but increased the organic C content of the fly ashes. Invariably, an excess of soluble salts and exchangeable Na could limit plant growth on fly ash dumps. Toxic levels of B and Al existed in only some fly ashes. 相似文献
108.
109.
Distribution of radiotin (Sn113) in target organs and in the hepatic subcellular fractions was studied in sham and partially hepatectomised rats 72 hrs after the administration of tin (II) tartrate (2 mg Sn++, 10 uCi/100 gm body weight) intraperitoneally. The results indicate that in both the groups Sn113 was maximally accumulated in liver followed by kidney and spleen. Partially hepatectomised rat however accumulated less Sn113 in liver while an increase was observed in kidney. Subcellular studies showed significantly high affinity of tin for microsomes. A compartmental shift of radiotin from cytosol to microsomal fraction was observed in hepatectomised rats when compared to sham operated rats. 相似文献
110.