全文获取类型
收费全文 | 1600篇 |
免费 | 55篇 |
国内免费 | 474篇 |
专业分类
安全科学 | 79篇 |
废物处理 | 102篇 |
环保管理 | 101篇 |
综合类 | 751篇 |
基础理论 | 267篇 |
环境理论 | 1篇 |
污染及防治 | 672篇 |
评价与监测 | 66篇 |
社会与环境 | 56篇 |
灾害及防治 | 34篇 |
出版年
2023年 | 30篇 |
2022年 | 89篇 |
2021年 | 86篇 |
2020年 | 38篇 |
2019年 | 47篇 |
2018年 | 55篇 |
2017年 | 75篇 |
2016年 | 68篇 |
2015年 | 70篇 |
2014年 | 116篇 |
2013年 | 157篇 |
2012年 | 111篇 |
2011年 | 143篇 |
2010年 | 94篇 |
2009年 | 106篇 |
2008年 | 108篇 |
2007年 | 107篇 |
2006年 | 84篇 |
2005年 | 57篇 |
2004年 | 62篇 |
2003年 | 57篇 |
2002年 | 33篇 |
2001年 | 43篇 |
2000年 | 44篇 |
1999年 | 35篇 |
1998年 | 36篇 |
1997年 | 25篇 |
1996年 | 28篇 |
1995年 | 20篇 |
1994年 | 17篇 |
1993年 | 17篇 |
1992年 | 8篇 |
1991年 | 17篇 |
1990年 | 16篇 |
1989年 | 7篇 |
1988年 | 11篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 2篇 |
排序方式: 共有2129条查询结果,搜索用时 15 毫秒
991.
采用电解锰废渣中分离出的一种锰抗性强的微生物Fusarium sp.浸取电解锰渣中的锰。研究了不同矿浆浓度、微生物生长活动、锰渣和培养基等对锰浸取效率的影响。结果表明,接种体积比为2%(v/v)时,矿浆浓度(m/v)对锰浸取效率影响显著,矿浆浓度过低(〈2%)或者过高(〉10%)对锰浸取效率都有不利影响。矿浆浓度为10%时锰浸取效率最高,达80%以上;微生物的生长活动对浸取过程有显著的影响;而锰渣的存在则能在一定程度上影响溶液的pH,进而影响锰浸取效率;培养基对锰浸取效率的贡献达50%左右。 相似文献
992.
993.
994.
生物浸取电解锰渣中锰的研究 总被引:5,自引:2,他引:3
为了评价生物法浸取电解锰渣中锰的可行性,利用锰渣土壤中筛选出的2种锰抗性强的微生物Serratia sp.和Fusarium sp.浸取电解锰渣中的锰,并采用优化的BCR(European Community Bureau of Reference)连续萃取方案对浸取前后的金属锰进行形态分析,研究其浸出率和浸取前后锰的形态变化特征。同时考察了3种萃取剂EDTA、HNO3和CaCl2对锰的萃取效率及萃取后金属锰的形态变化。研究结果表明,Serratia sp.和Fusarium sp.对锰都表现出一定的浸取能力,Fusarium sp.的浸取能力尤为显著,3 d后锰浸出率达到56.5%,为锰污染的微生物治理和资源化利用提供科学依据。3种萃取剂对锰的浸取效果为EDTA>HNO3>CaCl2,平均萃取效率依次为50.0%、28.8%和21.2%。浸取前后,酸溶解态锰所占比例变化较显著,说明酸溶解态锰是比较容易浸取的形态。 相似文献
995.
Yushan Su Hayley Hung Kenneth A. Brice Ky Su Nick Alexandrou Pierrette Blanchard Elton Chan Ed Sverko Phil Fellin 《Atmospheric environment (Oxford, England : 1994)》2009,43(39):6230-6237
Atmospheric PBDEs were measured on a monthly basis in 2002–2004 at Point Petre, a rural site in the Great Lakes. Average air concentrations were 7.0 ± 13 pg m?3 for Σ14BDE (excluding BDE-209), and 1.8 ± 1.5 pg m?3 for BDE-209. Concentrations of 3 dominant congeners (i.e., BDE-47, 99, and 209) were comparable to previous measurements at remote/rural sites around the Great Lakes, but much lower than those at urban areas. Weak temperature dependence and strong linear correlations between relatively volatile congeners suggest importance of advective inputs of gaseous species. The significant correlation between BDE-209 and 183 implies their transport inputs associated with particles. Particle-bound percentages were found greater for highly brominated congeners than less brominated ones. These percentages increase with decreasing ambient temperatures. The observed gas/particle partitioning is consistent with laboratory measurements and fits well to the Junge–Pankow model. Using air mass back-trajectories, atmospheric transport to Point Petre was estimated as 76% for BDE-47, 67% for BDE-99, and 70% for BDE-209 from west–northwest and southwest directions. During the same time period, similar congener profiles and concentration levels were found at Alert in the Canadian High Arctic. Different inter-annual variations between Point Petre and Alert indicate that emissions from other regions than North America could also contribute PBDEs in the Arctic. In contrast to weak temperature effect at Point Petre, significant temperature dependence in the summertime implies volatilization emissions of PBDEs at Alert. Meanwhile, episodic observations in the wintertime were likely associated with enhanced inputs through long-range transport during the Arctic Haze period. 相似文献
996.
Chong-Shu Zhu Cheng-Chieh Chen Jun-Ji Cao Chuen-Jinn Tsai Charles C.-K. Chou Shaw-Chen Liu Gwo-Dong Roam 《Atmospheric environment (Oxford, England : 1994)》2010,44(23):2668-2673
Fine particles (PM2.5) and nanoparticles (PM0.1) were sampled using Dichotomous sampler and MOUDI, respectively, in Xueshan Tunnel, Taiwan. Eight carbon fractions were analyzed using IMPROVE thermal-optical reflectance (TOR) method. The concentrations of different temperature carbon fractions (OC1–OC4, EC1–EC3) in both PM2.5 and PM0.1 were measured and the correlations between OC and EC were discussed. Results showed that the ratios of OC/EC were 1.26 and 0.67 for PM2.5 and PM0.1, respectively. The concentration of EC1 was found to be more abundant than other elemental carbon fractions in PM2.5, while the most abundant EC fraction in PM0.1 was found to be EC2. The variation of contributions for elemental carbon fractions was different among PM2.5 and PM0.1 samples, which was partly owing to the metal catalysts for soot oxidation. The correlations between char-EC and soot-EC showed that char-EC dominated EC in PM2.5 while soot-EC dominated EC in PM0.1. Using eight individual carbon fractions, the gasoline and diesel source profiles of PM0.1 and PM2.5 were extracted and analyzed with the positive matrix factorization (PMF) method. 相似文献
997.
Nguyen Cao Don Hiroyuki Araki Nguyen Thi Minh Hang Hiroyuki Yamanishi Kenichi Koga 《Environment, Development and Sustainability》2008,10(2):219-231
Groundwater is an important resource in the alluvial coastal lowland plains. In the Shiroishi lowland plain, southwestern
Kyushu Island of Japan, land subsidence due to groundwater development has long been recognized as an environmental issue.
Land subsidence can have several negative economic and social implications. In this study, an integrated numerical groundwater
and land subsidence model, which combines a three-dimensional numerical groundwater flow model and a one-dimensional soil
consolidation model, was used to simulate the dynamic groundwater flow and ground subsidence due to pumping. On the other
hand, a groundwater optimization model was also formulated to search for an optimal safe yield of groundwater pumping without
violating physical, environmental, social-economic constraints. The model results reveal that groundwater levels in the aquifers
greatly vary from season to season in response to varying climatic and pumping conditions. Consequently, land subsidence has
rapidly occurred throughout the area with the central prone in Shiroishi plain. The study also proposes a countermeasure against
subsiding process in the area by means of numerical models. The optimization model result suggests that pumping can be increased
in the northern part of the study area without leading to significant land subsidence. 相似文献
998.
Impact of land use and land cover changes on ecosystem services in Menglun, Xishuangbanna, Southwest China 总被引:1,自引:0,他引:1
Changing the landscape has serious environmental impacts affecting the ecosystem services, particularly in the tropics. In this paper, we report changes in ecosystem services in relation to land use and land cover over an 18-year period (1988--2006) in the Menglun Township, Xishuangbanna, Southwest China. We used Landsat TM/ETM and Quickbird data sets to estimate changes in ten land use and land cover categories, and generalized value coefficients to estimate changes in the ecosystem services provided by each land category. The results showed that over the 18-year period, the land use and land cover in the study area experienced significant changes. Rubber plantations increased from 12.10% of total land cover to 45.63%, while forested area and swidden field decreased from 48.73 and 13.14 to 27.57 and 0.46%, respectively. During this period, the estimated value of ecosystem services dropped by US $11.427 million (approximately 27.73%). Further analysis showed that there were significant changes in ecological functions such as nutrient cycling, erosion control, climate regulation and water treatment as well as recreation; the obvious increase in the ecological function is provision of raw material (natural rubber). Our findings conclude that an abrupt shift in land use from ecologically important tropical forests and traditionally managed swidden fields to large-scale rubber plantations result in a great loss of ecosystem services in this area. Further, the study suggests that provision of alternative economic opportunities would help in maintaining ecosystem services and for an appropriate compensation mechanisms need to be established based on rigorous valuation. 相似文献
999.
1000.
An experimental study on using rare earth elements to trace phosphorous losses from nonpoint sources
Controlling phosphorous (P) inputs through management of its sources and transport is critical for limiting freshwater eutrophication. In this study, characteristics of exogenous rare earth elements (REEs) and P and their losses with surface runoff (both in the water and sediments) during simulated rainfall experiments (83 mm h−1) were investigated. The results revealed that on average most REEs (La, 94%; Nd, 93%; Sm, 96%) and P (96%) transported with sediments in the runoff. The total amounts of losses of REEs and P in the runoff were significantly correlated, suggesting the possibility of using REEs to trace the fate of agricultural nonpoint P losses. 相似文献